I've recently been looking into getting a Matrix GT800FX power amp to use with the Pod HD Pro for live use, however im confused a little about how to setup the outputs for this situation.

http://matrixguitaramplification.com/products/gt800fx-instrument-amplifier/

The power-amp offers no 'colouring' and is designed for use with amp modelling such as POD and Axe Fx, does this mean I should use the STUDIO/DIRECT output setting when plugging into it?

I will be plugging the GT800FX into a randall 2x12 cab, however the cab i have uses Celestion Seventy 80's, which were the best reccomended for 'neutral sound' (used as extention for Vetta combo)

So in all, the power-amp and cab will be offering very little in the way of 'colouring' the sound. Which is the best output mode for the HD Pro? STUDIO/DIRECT, COMBO/STACK FULL, COMBO/STACK PRE?

Cheers.