I'm a bit lost on the scuba/snorkel analogy, but it's early here!
If your camera supports RAW and you have a way (any way) to get that image into your editing software, then I would use RAW. With RAW, basically, the camera captures all the information of the scene and doesn't throw stuff out. YOU then choose things like white balance etc at the software level (this would normally be done by the camera...and the camera has presets so even for the stuff you choose, you don't have the full options).
I don't know anything about PE3 so can't help there. But you are doing your images a disservice in the future if they aren't in RAW now. I so wish I had started RAW immediately instead of waiting until I "knew more" or was "better"!
If your software won't give you total control over your RAW images, but will let you get them into your software, you are still better off than shooting SHQ. Why? Because you'll still have pretty much the same image you would have had shooting SHQ, but you will have way more information saved in the file. So it gives you more to work with right now and you'll have all the information to work with in the future when you upgrade your software so you can revisit your images.
My theory is why throw away perfectly good data (which is essentially what shooting SHQ & other jpeg formats does.)
I don't know if I have explained it right or not...I don't get all the technical details, just the outline! HTH