Oh yes, dove with them many times, i lived there for 3 years....
As for how high he does his fills i am not sure. They have a membrane, helium, and pure O2 on island so shouldn't be a problem, but not sure of their policy on CCRs at all.
They can also drop you off on a beach with camping supplies if you want and pick you up the next day for diving. You are certainly not too far off to be making these plans as one year in advance is a regular for us out here.
June is a relatively slow month anyway so shouldn't be a problem booking. If you want to do a bare bones charter on a sailboat that is also an option, again it is through Sam's, you can charter the boat for just the two of you if you want. For some reason i can't think of the name at the moment, check in the Australia/Pacific Islands section, there are some threads on it there. It is also mentioned on the Sam's site.
PM me and i will send you Matt's personal email so you can talk to him directly. He may be at DEMA but not sure, Sam will be for sure
Best