Guy! I'm glad you got a Wiz. I love mine. I did notice however you have some issues. I don't know why you can't use SDHC. You should since all 4 of my SDHC cards work in my GP2X WIZ.
Also for Temper there is a fix that was going around on the forums. The stuttery sound is not the emulator but the system itself. There's a ram timing fix that will work. When I get time I'll PM you and send you the fix. Then it should work perfectly. I can't find the link for the fix off the top of my head on the gp32x forums. Also you should underclock the emulator. It defaults at 533mhz. I have mine clocked back to between 400-450 mhz for most games. Quite a few can be underclocked even more. I don't know why it works better underclocked but it does.
Now regarding file size for your cd games. I guess you're ripping your original to bin/cue. To save space I rip them to iso/ogg. The Temper emulator should've came with a iso ogg program. I rip my games from cd to bin/cue, then use the converter program that came with the emulator to convert it to iso/ogg. I don't believe it does mp3 for audio tracks. There should also be a link in the readme for the ogg codec used to convert the bin/cue files. I hope this helps. Temper really is the best pce emulator i've used actually. Just as good as Magic Engine in my opinion. (minus the extra options for visual effects/ audio balance etc) It is the only emulator for pce on a handheld that does ACD and other CD games to near perfection. The ram timing fix really does fix the stuttering issue. It's a fault of the system, not the emulator. Temper on my regular GP2X runs perfectly. It's the Wiz version that has this stuttering issue, but it's a hardware issue.