Pat, I just unearthed my old kits of the 1/35 Tamiya SdKfz 222 and 223 from the 1970s, and I have to tell you that they are inaccurate too when compared to the plans in Panzertracts. The turrets are better shaped and the hulls are a bit wider, and the chassis parts in particular are nicely done, but the '222 has no interior at all except the turret gun mount, and the '223 interior is a total fabrication. There should be a gun mount for the MG 34 and Tamiya has it just hinged on the front edge of the turret ring. Even for the '222 turret gun mount, the ICM kit has most of what the old Tamiya kit gives you, except the central post mounted on the hull floor. You could easily use the ICM mount parts to make the proper mount for the turret. The ICM mount seats appear to be more accurate based on Toadman's pix of the Littlefield '222. So, as far as accuracy is concerned, it's mostly a toss-up except for the more detailed chassis on Tamiya's kits.
Considering that the ICM kit chassis is similar to the Tamiya one without the smaller details, like the tie rods for steering, it is a good basis for a model. Yes, the hull is a bit narrow, but look at Konrad's built '222. Not magic, just a bit 'o modeling. I am sufficiently moved to try to find SOMEONE who actually sells these things so I can buy some more. With your already demonstrated skills, Pat, building one of these, even with Konrad's turret work, would be a walk in the park for you. Hell, I'm gonna try it and I'm half-blind close up.....
