Thank you for your opinions and advice, i'm finding them quite much helpful.
About the same aperture you are saying it would be the best, mostly I'm planing to use open aperture and blur the background, from f/1.8-2.8 for 'head-and-shoulders', and about f/4. for the entire body and wider frames because the lens are manual and focusing is pretty tricky. The rokkor 58mm has 1.4 but they are not as sharp as on 2.8
I watched some tutorials about making a bounce reflector, i'ts pretty simple, also i found they are pretty cheap on ebay, some Chinese with white/silver/golden side for 11 dollars which should be enough nice.
I'm not entirely sure about the film speed, I want to use Kodak Portra 400VC (as I read +1 stop most people recommend) or maybe 160VC which is finer, but i'm afraid if I haven't the enough speed, and I need some motion dynamic shots. Also maybe B%W film, or just to convert it after.
Negative print film would be better, also for slide film I need to have very right and correct exposure, and I wouldn't use it for first photo-shoot of this kind.
I will look forward for trying to use the medium format KIEV 80 but first i would make sample test photos to see the exposure, colors, focusing, sharpness.