If I'm switching out the stock hooks on a crankbait, & I want to use 2 different sized treble hooks; 1 of them a size bigger, which end should the bigger & 1 size smaller go?

Do I want a bigger hook on the belly or on back of the crankbait?

And if I use a 1 size smaller to compliment the bigger hook, does that go on the belly or the back of the crankbait?

Or do you keep the same sized trebles for the belly & back?

Depends on the bait-

If it is a diving bait and you want it to go deeper, put the bigger book in the belly, giving it a more nose down attitude. Wake baits or cranks you want to run shallower, reverse and put bigger hook at butt end raising nose. Sometimes this will screw up the action so don't pitch the hooks you took off until you try the bait.

Personally the only time I upsize the stock hook sizes is on lipless baits as I will go one size larger on the belly to help free weeds easier, however I would suggest never upsizing the rear treble on any bait as all fish imitating baits should sit/run nose down no matter what in my opinion.

Even wake baits will run nose down as the tail is what creates the wake.

Steve