Sorry, no pics, but I disassembled, and added some delrin washers and metal washers(IIRC they were small 1/4 20 washers). Trial and error because I added washers until it would not cock, then took some away one by one until it did cock. It was a few months ago so I cant remember exactly the total spacing. I think most of the spacing was in the front of the spring, but it is nice to put 1 or 2 metal washers (if you can make/find one) in the rear of the spring so it can rotate freely. Caution: kick becomes more pronounced because of the added weight inside of the piston. Kick probably could be reduced by just measuring total front spacing and then making a tophat out of delrin to match that spacing, and then take the washers out so there's not so much wieght. Now that I have a lathe I guess I can do that one of these nights when I'm restless. Lots of restless nights comin up in the fall/winter. Thats when I do my best work, but I have neglected to take notes...so in the future I will try to document my travels/experiments so that when folks ask questions I can give a better answer. LOL...I'm sure most folks dont wanna be tearin down their 5G to put in washers, put it back together and then tear it down over and over until it cocks...
There is perhaps an easier approach now that I've done it... Put the spring on its guide and put it side by side with the tube so you can measure the space from the begining of the spring guide seat to the end of the front of the tube, then subtract the stack height of the spring. That will get you in the ballpark...it might even cock the first try if you subtract an eighth of an inch or so from the space.
Hope that makes sense, if not, try the trial/error method...thats how I did it.