In all reality, it should work fine to run say a 10 lb. main, and 10 lb. leaders. It is nice to have a stronger mainline though, as the overall stretch factor goes down when you start getting into heavier monos. Thus, making the "feel," better. Spiderwire is a braid. If you are running Spiderwire as a main, like it appears you say in your post then you have braid, not monofilament.
Drift fishing, I run 12-15 lb. Maxima UG, and 6-10 lb. Sufix Siege, or UG leaders. There is a reason nothing has changed in UG's makeup, and composition over the years, and Siege is ridiculousy tuff, super tuff.. Thats why I run those two brands in particular. I recently tried some Gamma in the Hi-Vis, and the only real good thing I can say, is that it never comes off of the spool more than one loop at a time, so if you birds nest a lot, look into this stuff. It also works extremely well in sub freezing conditions. Needs some abrasion coatings, or a tougher chemical make-up though.