Hi DaFireMedic,
Having a zoom is definitely a nice feature on any camera. However, I can totally understand that you don't want the hassle of drilling a hole in the housing and later the testing for leaks etc.
There are several ways that you can try to white balance:
If you are at a site with whitish sand you can try to use that. It usually works quite well.
If you're not in sand, you should try to carry a white slate or get yourself white fins to point the camera at. Try to get your camera lens as close as you can to the white object without casting too much shadow. The greater the white area in your viewfinder, the better the WB will be.
- Try the palm of you hand as another alternative if you don't want to carry a huge white slate or don't like white fins!
- If all that fails, you can try to point the camera into the sun and WB using that bright spot at the center of you viewfinder.
Test test test - I'm sure you'll find one or the other quite acceptable, despite not being exact. Let me know how it went!