I put this up in the Traxxas RTR section, but I noticed it didn't have a ton of traffic after I posted.

Ok folks, I picked up a great condition used Spartan for my 11 year old for Christmas. I want him to spend his time having fun instead of tweaking for speed, so we are staying 4S. In addition, I have tons of 2S and 4S packs for racing cars, but zero 3S packs. I have done some looking for recommendations on prop selection for 4S, but have struggled to find much. Most discussions are around attempting to attain speed on 6S.

I am wondering about slightly larger diameter or 3 blade prop instead of 2? Right now it tends to be pretty slow out of the hole with ok speeds. Remember, this is for a 4S system. I don't plan to drop $$$ on a bunch of 3s packs just for the boat when I have tons of 2s packs!

Props I have seen mentioned explicitly for 4S is Y547 or M445, also saw X442 as near identical replacement to stock dimensions.

Boat info:
Stock TRX ESC and motor
Stock motor cooling jacket
Dual pickup and outlet on order, will be here this week.
TRX adjustable trim tabs on order, will be here next week.
Will be running inner and outer tabs
Stock turning fins
Stock stinger
Currently on stock prop

Testing this weekend seemed to show that outer trim tabs have minimal affect on boat attitude when its up on pad. Battery location and stinger angle had far more effect. Ran packs from full forward to full rear and multiple stinger angles at each position. Found a pretty wide operating range that was suitable, just some were a touch slow out of the hole. Boat handled well and only had minimal chine walk on the most extreme range of bow lift.

Any experienced input or firsthand testing knowledge would be much appreciated!