I couldn't find any useful sources by googling, so here's my question:

You run 4 copies of Leyline of the Void. I want to increase the chance to get it in my opening hand, but don't have the SB space to run a full playset of Serum Powder.

How much would the chance to lay down a Leyline on T0 increase, if you run a) 2 copies and b) 3 copies of Serum Powder, assuming you don't want to mull down lower than 5 (or 4 cards) total?