many people use klotz super techniplate and you will absolutely not go wrong with it. it smells very good on top of it. Technology hobbies sells it by the gallon for $45.
not sure if this would work for you but its a square insert for standard collet
https://zippkits.com/index.php?main_page=product_info&cPath=85&products_id=608
do not use EC5 they are too small for out boats. Get QS8, 8mm bullets, EC8
these are the best Ive ever seen and I highly recommend
https://www.smc-racing.com/index.php?route=product/product&path=66&product_id=762
it looks like an 1/8th scale so it will use 8s. 850kv is about perfect something like a TP 4070 or a 5692 rocket RC motor. the goto bad boy ESC is a Castle XLX2. budget esc ZTW 200A. I'd personally get a set of SMC HCL-HP 4s packs wired in series for it.
netting was an experiment to collect leaves and debris. it caused too much drag and its gone this season. motor pictured is a 3536 I think. It now has a 3548. It is about 24" wide I think.
I retrieve gas cats, hydros, backlashes, etc with this. I made it 4s with a 12x5 prop this year for more weight and power. it will in fact push or pull a full size jon boat.
these are actually pretty nice I have a couple, actually nicer than real zenoah stuf IMO. Takes about 7-10 days for shipping though.
https://www.tit-racing.com/collections/rc-boat/products/gas-engine-cooling-jacket-cover-fits-zenoah-g260pum-for-marine-engine
EDIT: NM cant use the knockoffs