First, I've decided to lengthen the building ten feet. This will net me about twenty-four feet of internal work space which is more than long enough for my purposes. It's also a better fit for most automobiles so this is a logical decision.
If I can't find affordable Rodagon-G's I guess I'll have to try normal taking lenses. Maybe they'll work well at high magnification. I'll find out once I have the building lengthened and set up a darkroom.
Any more advice is greatly appreciated... or if you have a nice 150mm or 300mm Rodagon-G you want to sell on the cheap then please let me know before I spend all my money on booze and ladies!!
A little more research and trying to drill information into my thick skull... It appears that a standard Componon-S or similar will work fine for 8x10" at 12-16x magnification but I'll need a Rodagon-G or similar for enlarging 6x12cm to 25-30x. Gee whiz... it may be cheaper to shoot 8x10" all the time.