I figured out how to solve my issue. I had to revert back to a build of Dolphin 4.0 that still included support for Direct3d9. I used 4.0-146 and now everything is working great.
If there's no way to import custom textures without resorting to D3D9, that should be reported to the developers as D3D9 is no longer supported in future updates of Dolphin, in favor of DX11. Losing the ability to import custom textures would be a major drawback.
Cool. Will try that out when I get to the game.
Another option is playing with KB/mouse, mapping the pointer to the mouse, and mapping wiimote tilt to mouse2+mouse or something similar - this works for a lot of games that don't use all three of Yaw, Pitch and Roll. I do this with some games and it works pretty well (I also usually map the mouse wheel click aka mouse3 to a shake in all three axis when doing this).
For example, something like the above along with WASD, Shift and Ctrl for the nunchuck, Q and E for + and -, and mouse1 and Space for shooting stars and jumping, respectively, could work well enough for most levels of Mario Galaxy 1 or 2, depending on how much you depend on completely analog movement.
edit: another remark, regarding Bluetooth - if you can borrow a Wiimote from a friend it would be best to just test and see if your current BT stack is supported. That would be the ideal case and a lot of the times it works with Dolphin with very little extra effort.
Another option is to download a free software called GlovePie which communicates with Wiimotes via BT as well, and may have support for additional BT stacks that Dolphin does not.
is it possible to set the IR to the right stick without it putting the star aimer thing right in the middle of the screen? basically is there any way to make it auto hide when im not touching the stick?
also can you explain the "hold LT while using stick" for tilt thing? i'm not really seeing how to do that. thanks
It seems other posters have already figured these out for the most part, using "!+button" in order to hide the pointer, etc, is what most of us do.
regarding tilt, if you open the emulated wiimote configuration window in Dolphin, you can map tilt, shake, and swing, per axis to different KB or gamepad button combinations. You can also do this for the nunchuck via the "extension" window. Right clicking the buttons instead of left clicking them opens up a menu that lets you set up complex combinations such as {(A or B) and (X or Not Y)} etc. Experiment with these to see what you like best, and don't forget to save your configuration when you're finished making it!