I just got an email from mike and he said that the 18-24 tooth gears are hardened so if you get the robinson slipper and spur you could get the 65t steel and that would be very strong.
I ordered some parts. It will be a mix and match time though. I got the Robinson double slipper in the Emaxx 65 tooth and the Associated Monster GT in 54 tooth. I am hopping for the GT one to work. I ordered 32 pitch 18 tooth pinion. I also got from Mike a 20 tooth Mod 1 pinion and a 52 tooth Ofna spur gear. I am hoping I can swap the 54 tooth for the 52 tooth and use Mod 1 gearing. Mike didn't have any 32 pitch pinions over 18 teeth in stock. But if the Ofna spur gear works I am on the right path Mike set me up with. Cross your fingers.
you could get the 65t steel and that would be very strong.
Stay away from steel spur gears. It is best to keep the spur gear plastic as it is an easy and inexpensive weak point to replace. Going with a steel spur gear moves the weakest point to the transmission, which is much more time consuming to repair and most of the time more expensive.