I used to get max top end with an old WMMOL series 28p Lightning ET. But it got damaged not once but 3 times in 12 months, the last time being my rock climbing adventure with my SS2000comp. Fixed it again, but it's just not quite the same...barely. It was my favorite prop and seemed to run great on every Allison I put it on. Back to your question....
The 109 top end was run with a 28 Hoss Triton that was supposed to have been modified by Dave Bostic (RIP) into a 30p. Several prop experts that I have talked to say this is not feasible because you can't bend the prop root, and that likely it's more of a 29.
Ran 108 all day long with a 26p Hoss Triton, just higher rpm's.
Yes the starboard side is the prop on its way down where it hits the water and bites. The filling of the holes prevents vortices of aerated water from heading into the prop. I picked up at least 2mph with this mod! That's huge at 100+ mph. To quote Todd Bucknell..."would you rather have the prop bite into cool whip...or water?"
Always have run with the fairing.