If you want a real bargain look at Wollensak 1a triple convertables---that will give you all the focal lengths you're after in one lens/shutter for probably less than $400 and it is a very capabl performer indeed! G-Clarons (especially the 240mm)and Commercial (14") and WF(250mm/10") Ektars are always excellent choices but the prices seem to be climbing out of site, so if you happen upon a good deal jump on it. Another option is the convertable Symmar and of course the Dagors 12" And 9-1/2" Dagors occasionally show up at dealers for reasonable prices. Another lens to look at is the apo artar, not nearly as costly as the red dots but excellent none the less. My 14" APO will cover 8x10 with some wiggle room, and don't forget 12" Wollensak Velostigmats and 375mm Ilex Acugons. All these are lenses I'd be happy to use (if fact I do use several of these) and there are examples around which shouldn't break the budget. Take your pick and run with it!