I want to use an SVP-PRO or SVP-CL preamp with a QSC Pro Amp. Should I connect them with XLR out or the 1/4" output? Also while we're at it, SVP-Pro vs SVP-CL? I'm leaning towards the Pro just because of the Drive funtion for a bit of distortion and the reassuring fact it has more tubes than the CL. What are your thoughts?