Tights lows and a Big Muff Pi

First of all I did do a search on the forums but I can't find the exact answer for my question. My apoligies if this question is already asked tough

Lately I've been thinking about using my Big Muff Pi again. Problem is that I like a bass sound that is as chaotic as the fuzz makes it. But on the other hand I would like to keep my lows tight (and present). I was thinking about fixxing this problem by splitting my channel. Like Tu-2 -> Akai Headrush 2 and then 2 signals out of that. 1 signal staying clean the other signal going to the big muff. The problem which I then have is bringing it back to a mono signal again (since my Ampeg SVT II (np) only has 1 available channel. Could a Boss Ns-2 or Ls-2 do that? Would be nice if there would have a blend knob to control the volumes of the signals.

P.s. Already have a Big Muff and Headrush 2

Thanks