Powerheads and water flow

Hi, I have a Wavemaster Pro, and I have been using Hagen 301 powerheads.
I now have a sump, wth a Mag 7 with about 4 feet of head, but am still
using the powerheads to get more flow.  The Hagens start a little loud,
and need frequent cleaning to keep the impeller starting with the
wavemaker.
Questions:
1. What  powerheads are others using with wave makers?
2.  Currently, my sump returns via a Magnum J-tube, which only puts out
in one fixed direction.  What return options are there that would give
me more versatile flow?
3.  How can I get more flow to the back of my tank?  I have a canopy
that covers the rims on the front and sides, so I can't mount them on
those sides.  I have no luck getting the suction cups to stick.  Does
the magnet trick work?
Thanks,
Elizabeth