Ye recon your maths is ok

Just my experience, cant say thick walls etc aint worth it, just I wernt gonna replace mine untill they broke which they never did

Ok was gonna replace them regardless even when they wernt broke but was told that they couldnt guarantee them that I wouldnt break them on my first launch, so thought what was the point of doing them unnecessarily

On the gearbox front what makes you think you would break a big tooth, tis one of the stronger boxes for the sort of money they cost, ok know you could spend more but the bigger benefit you would get is quicker changes as said didnt break mine after it had been rebuilt properly