I had several sets of connecting rods to chose from when reassembling my R90/6 engine several years ago. I used a pair of parallels resting on the flat surface of the block and the wrist pin in the small end, I rotated the crank with the alt bolt until the wrist pin could contact the parallels. I could see where the rods were a little bent because the parallels didn't both stay up when held by the wrist pin pressing against them. I placed a long rod in the small end and bent the rods till they were straight. I performed this little trick on both sides several times, until the parallels were only lightly contacted and I wasn't holding them up by excessive force but they were contacted by the wrist pins at the same time.
Been running engine now for 3 or 4 years maybe. It had a lot of vibration the first year but that has gotten better over time. It is pretty smooth these days.
I suppose I should have checked for an even TDC between the two sides. I never did but since then I have found the tools to do that. I have a degree wheel and a correctly fitting TDC bolt set up. Still engine is running pretty good so I probably won't do that right now.
If you really want to do a correct rod reconditioning then send them to a shop that does rod reconditioning. I don't think my little operation is as good as the real job but I don't think it hurt things any and may have made them better.