Are you using the other 'secret' ingredient, low melting point solder?, e.g. Javis LMS 145 designed for brass. 138 deg solder paste available readily from ebay from China.
Nice progress Glenn, I have to keep reminding myself that it's 1/144!
The battery on my electronic calipers is flat so I can't measure the drill size that would be suitable. But it should be really small, very much smaller than the holes on the 144th kit.
Going by your photos the 12 holes on the Revell kit they look too far forward to me. When you drill new ones it would be best to position them a bit farther back. Perhaps you could align the first hole with the front of the torpedo door?
U 215 was a Krupp boat and had 12 equally spaced holes on both sides.
Glenn, would you be willing to post a link to that facebook album? perhaps we can pile on the idiot and try to explain to him the difference between an individual who wants to build the best model his skill set will allow him to (and maybe even learn a few new skills) and nit-picking someone else's attempts at model building...
Great to see the progress Glenn. Enjoying the updates.