So I have two sets of battery boxes now. I made a set of boxes that are a bit smaller, they allow for batteries that are 32 mm in thickness max. Perfect for most 3S and 2S packs. If I ever want to run two large 4S lipos in parallel for longer run times then I just put the large boxes on. I will trim that middle skid under the battery boxes so that it doesn't stick out the way it does now.
Other stuff came in today, the bearings for the Muggy steering, the Traxxas motor plate and motor mount. I thought of a simple way to support the back of the motor. It's not as pretty as the kit I posted earlier but it will work.
This set up should work well for steering, there is a lot of weight to the front. Once the conversion is done, I suspect that close to 60% of the weight will be to the front.