Which screens do I really need?

Hey this is about which size Lpi screens I need if I plan to only buy two maybe three of the 2x4screens to use as a table top setup to bust all my herbs up over with scissors. I want to support fresh headies but I would rather spend half the amount on 2 instead of 4 screens. I also am not really sure which screens are really essential. I'm trying to get my sift stronger as I currently use a Wikka box with a 100 monofilament screen and it collects a decent return ratio but the sift is no where near bho when dabbed or when infused. The goal is to decide on a new set of screens to get my sift on point so I can get the same relief as bho. I think it just needs to be further decontaminated right? I would also like a tumble now for this purpose but only have a 90 g limit and don't want to spend 500 when I think I can do the same with 100$ worth of screens and some time spent chopping and carding

do I need all four screens that come in the medium set or can I do the same thing with two or three?
Thanks