Electric mountain bike questions

[BL_RV0]

Bringing this thread back up. I'm going to change this design a lot. Planned setup is Ben's monster motor with gear and sprocket reduction, 12v 30ah lead acid batteries and a 30a 36v e-scooter controller (I have all of this sans the motor). The gear reduction will me 15/81 using mod1 gearing on 8mm shafts (only combo that SDP-SI had that make a good speed). This will be achieved using PNs: S10T10M015S0508 and S10T10M081S0508 as the pinion/spur respectively. The next/final reduction will happen using the 32T rear sprocket on my bike and PN A 6M 7MHZ12713B as the "pinion" sprocket, yielding a 13/32 reduction. Ben's motor is 380Kv and will be used on 12v 30ah yielding 30mph, but probably less when IR is factoured in. I'll use some #40 chain to run from sprocket to sprocket. All of these components will be mounted in a large box on the rack over the rear tire, and crank mechanism will be removed and pegs installed. Only thing I'm worried about is my 13T sprocket- it's acetal resin with a brass insert. Will this work or will all the teeth shear off under load? I can't find a metal one with the same spec for the life of me. Quite a strange sprocket though- 8mm bore, 13T, and #40 (1/2") pitch. What do y'all think?

PS: I have 3 12v 10ah packs, so I can run 12v 10ah, 20ah or 30ah.