tri bike to road bike fit - same manufacturer

Due to a recent bike-totalling crash, I am shopping for a new bike on the cheap.  I was previously riding a 58cm P2C (fit by a FIST certified fitter), and have a potential deal for a used soloist frameset also in 58 inches. 

I would plan to set the bike up as a normal road bike without aero bars.  I am 6'2" tall if that helps anyone.  On my P2C I rode with the saddle as far forward as it would go, leading me to believe I barely made the 58 and almost needed a 56.

Given the saying [wives tale??] that you are usually the same size road bike as a tri bike, or maybe one size larger, my gut feeling is that the 58 cm soloist should work for me.

I appreciate any insights, short of going to get fit for the road bike which is not currently feasible financially.  My goal is to get into a good quality cheap road bike for as little as possible, and then begin saving for a new P2C.

Thanks,
Josh