I reported the findings of your first run with the Capsaddle, and didn't see where the Capsaddle had any negative effect, only positive effect. I didn't editoriallize during the report, preferring to relay your report to me, but I might as well provide some opinions now, based on the info learned, since it may affect the course you are headed on, reference old threads:
Two weeks prior to installing the Capsaddle, you raced that 390 block at an NHRA event and found all cylinders were critically thin and problematic. It was the first time you raced tht recently acquired engine, if I recall. You took the necessary step to fill the cylinder jackets with an industrial filler to fortify the bores. At this time you also installed the Capsaddle, following my instructions very effectively. Analytically, this is a bit of a risk, because you made two changes to the block, thus making it more complicated to troubleshoot any problems which may have occurred. Still, it remains a worthwhile experiment, as long as you are willing to take the added risk, and also as long as we set the analysis filters properly. Along similar lines, I mentioned Wes's "poor man's 427" project should not use a Capsaddle for this very reason, as any failure would be difficult to trace to an origin, and it seemed he could not afford the risk. The Capsaddle remains untested, except for your build.
When you raced the rebuilt 390 two weeks later, the block was freshly filled and the Capsaddle was newly installed. You reported the main bearings "all looked good" after the race. This made me happy, but I could not state my happiness, as I needed to report the analysis matter-of-factly.
The #2 rod bearing had failed (nearly spun), but this would seem unrelated to any Capsaddle event, and most likely related to using the oddly modified "cross drilled iron" crank which came with the engine. Iron cranks which have been redrilled to become cross-drilled tend to have poor reputations. Additionally, you were logically using the rods that came with that engine when you received it, and I suspect they were stock. If so, it is possible the selected bearings had the notches in them which would allow the crosssdrilled crankshaft to squirt twice each crankshaft revolution - both times positioned far from the correct position for squirting the cylinder walls as originally intended.
An addendum is in order. The "squirt hole" I refer to is found on all FE production rods except the LeMans rod used in 427 sideoilers. The squirt hole is in the big-end of the common FE rod, at the parting line of the bearing shell halves. With a regular nodular iron crankshaft, the oil feed hole aligns with this squirt hole once each crank revolution to momentairly shoot a quick stream of oil onto the cylinder wall. The LeMans rod did NOT get this squirt hole, mainly because the LeMans rod was developed for use with the forged 427 crankshaft which was crossdrilled. Again, cross-drilling messes up the location of the squirt, rendering it useless for assisting cylinder wall lubrication. The LeMans rod did find a unique pairing in the commonly-drilled 428SCJ crankshaft, and the squirt-holes were still not present, so it is clear that cylinder wall oiling via the squirt hole is not required, at least when combined with bearing clearances found in 427 sideoilers and 428SCJ engines. Note that all factory production sideoilers got LeMans or NASCAR rods and forged steel cranks. All factory production 427 topoilers got cast cranks and common nut-and-bolt rods.
Most critically, you noted that cylinders 6-7 were severely scuffed, less scuffing was on cylinders 2-3. More-than-normal scuffing could be found on all eight cylinders. You attributed this to Capsaddle oiling issues, but I fail to see significant probability for the connection. Recognizing the fan blade rotates clockwise, the crank throws would be most efficiently scraped by the Capsaddle as they passed cylinders 2-3, and it would seem there would be no scraping effect as the throws spun toward cylinders 6-7. I can also fathom no Capsaddle windage effect which would cause oil starvation at positions 6-7. My prime theory was that the cylinders of this block were too thin. It is also possible the industrial filler may have not been formulated to provide dimensional stability at elevated temperatures after the short set-up time - at least not with such thin cylinder walls to provide support. Perhaps industrial fillers are different from racing engine fillers in this application.
Most likely, I detect a sort of "siamesing" effect in the center cylinders which may have caused excess "heat soak" to distort the center cylinders into an oval only when hot, resulting in scuffing. These cylinders would likely return to perfect roundness when cooled. The center two cylinders on each bank have little neighboring mass with which to distribute heat energy. The four corner cylinders have far more surface area with which to dissipate accumulating heat, so they would not get as hot. More to the point, the four corner cylinders should have shown no excess wear if all had been kosher, since the windage of those cylinders is unaffected by the Capsaddle.
Cutting the diamonds out does not seem like it would cause problems, but it would make the Capsaddle more flexible, and I question whether it would work as well. I developed the oil drains in the small "pockets" of the Capsaddle to drain more rapidly than they can fill (based on the air-pulsing action of the throws as they pass), but, drained or not, I see no negative impact of the stock drains on performance or oiling. The failure you saw was simply not caused by the Capsaddle retaining oil in the pockets.
I'm not yet convinced the Capsaddle will benefit from any modifications. When I am able, I will be building a Capsaddled FE. For now, I remain unable to schedule any engine builds, or work much on any cars.