Greg,
I'm a little underwhelmed by the blade profile. I think the choil notch at the bottom is out of proportion to the size of the blade. If you increase it's length a lot, and height some, it'd give a better balance. It would set the blade apart from the guard and handle giving the knife a slim "waist".
On the guard. Salem's idea is great. I have forged a few spiral twisted tails on knives n such. If you take the guard and file two round bars and twist they will be organic and subtle. If instead you file the guard with two tapered squares on each end, twist them, then twist both it will add lots of ridges for texture. And fun to hand sand! Picture twisting a 1/4"x1/4"x2" square rod vs a 1/4"x2" round. Lots more texture in the square.
But... Your overall knife shape is more organic and less angular. So you could go with either style as a contrast.
A common way to work out metal shaping ideas is to use clay. It can be "forged" to figure out what you can do with a certain size of steel.
Some bladesmiths use clay to teach, and design damascus steel making. Get some clay and mock up your guard. Then bend, cut and twist until you get what makes you happy.
I hope you figure out your AO set up. Have a competent person show you how to install the regulators, adjust and test them, check your hoses etc. Following the basic safety steps you'll be safe.
Looking forward to seeing it progress.