I currently am running a 24 Honda with a 1.47:1 gear ratio, reason for this is the mini frame i used was geared for the 18 Vanguard and i just swapped engines. I use a 12x12 GDSD propeller turns it @ 3800 rpm and gets 24 mph. I was wondering if i would do better with the a higher gear ratio and the 11x10 or even a 12x10 propeller. I know that if i turn a 10 pitch more rpms, hence the higher gear ratio , i would get more speed. Now I am turning the 12x12 only 2585 rpm's (prop rpm's) with the lower gear ratio. So any help or advice will be greatly appreciated. O by the way i run a 1542 flatbottom boat.

Just my .02, but the way that thing is running I'd leave it alone. I think you're only gonna go backwards from where you are now.

I believe you are correct, might as well leave well enough alone. For the $$$$ i have invested it serves me well, $3500 invested roughly in whole rig. The reason I am asking is I do need a new prop, this GDSD prop is not balanced well and has vibration. I am thinking on trying the Ron Hill surface propeller versions, he makes a 12x10, 12x11, or 12x12.