Strobe placing is totally up to a person who is shooting because everybody has own taste. I pretty much always use softbox on main light. The size and shape depends on what kind of lighting you want to create. For this I would use simple 2 light setup where lights are 180 degrees apart from each other. Main light on off axis (maybe camera right for this) and about 45 degrees down. Other strobe could be with bare reflector. If the shadows are too strong, I would use sb on that. Purpose of second strobe is just to give nice rim on shadow side. Be carefull with rim light power settings. Too powerfull and it can easily burn away all the details. If you want to blow the bg and make it pure white, you will need 2 extra lights for that. They should be around 1.5-2 stops brighter than your main light. Gray bg could work for this image as well