Boost or Treble boost?

I been using mainly a Big muff pi (NYC reissue) for distortion lately and I love the fat fuzzy sound I get with my SG and this pedal but there are times I would like to have a little more definition, in my mids and highs without switching to a single coil guitar. I was just wondering if a boost pedal would give this or would I be better off getting a treble booster. my only concern with the treble booster is that I don't want to loose too much of my lows. Working on a budget so i'm looking at the EHX LPB-1 and Screaming Bird but may be able to afford a used MXR micro amp.

You could try a screaming bird, but a compressor would be better. Often when people switch between Single Coils and Humbuckers, they use a compressor. I use a Boss CS3, but Dyna Comps are good too.

That's pretty much the sound of fuzz. Maybe finding a similar sounding fuzz with a little more control over the tone would be my first choice.

But if you like the tone most time and just want something to put it over the top, I'd say a treble boost. A regular boost will will, obviously make you louder, but may or may not, change the tone much to what you want.

Personally I wouldn't combine a compressor and a fuzz together, that would suck the life out of the fuzz, IMO.

In my experience, the LPB is sort of bass-heavy. I don't this would apply for your needs.

An EQ pedal might be a better choice and could also be used as a boost if needed.

+1 for an EQ pedal