RE: X435 vs Y535
Personally I prefer the 3 blade props like the M435\3 especially on a Tail Heavy boat like the Miss Bud, because they tend to give more Lift to the transom which help keep the Bow Down,, But on Slick Water a 2 blade prop like the Y535 is a little better because it lets the Bow Float and run a little Looser. The X435 will not be enough Prop for the Go .18.
OffShoreElectrics.com often has those props available or FunRCBoats.com may have them also, Do a Google Search on em and you may find more places that have them available,,, Or shoot me a PM I have Both the M435\3 and Y535 S&B.