Well the best loop to do with him is the RDP+B [HD] air QCB+P.
Now for the most part the best version of it is corner only where you get to throw in some Fireballs after the dive bomb and before another DP to add some damage.
From around midscreen, you have to do RDP+D first in order to get the dive bomb to push to the corner. From a bit further out, you have to add a couple of rekkas. From full screen you have to start with two rekkas, do 1 hit of RDP+D, do two more rekkas, THEN do the RDP+D into dive bomb.
Of course, if you really want to get down to it, there's a trial mode combo where you can do the RDP+B [HDC] air QCF+P loop from anywhere, but you have to run in after the dive bomb before doing another DP until you get to the corner, and that's a pain.