I really like using a clean boost lately. I picked up a Baja Boost which is sort of like an old Rangemaster, but with a tone shaping control. Works great, adds some thickness and can boost mids if you set it that way. Not to spendy, under $100 on ebay.
I use a Boss OD3 as a Lead boost (level up, tone and drive down) in front of my Plus. I use a 10 band EQ in the loop for more tone shaping possibilities.