Ok so I finally started on this beast.
I decided to try the all metal Mato lower hull and mato tracks with extended end connectors and mato steel ball bearing 4:1 gear boxes.
The draw back to this hull, was the tracks would not fit over the bogies, I had to literally slide them on and pin them after they were in place.
Talk about a pain in the rear. Its like scale track repair without miniature guys to do it for you.
Its also quite costly compared to getting a HL as a donor tank.
To get the transmission cover to fit on the lower hull I soaked it in hot water and formed it to the hull. Unfortunately though it doesn't meet the upper glacies plate correctly, it also isn't quite thick enough or formed the way photos of the one I saw look so Im going to add a Tamiya bolt bar on top and build up the tranny cover with bondo to thicken it.
I am planning to use a HL rotation gear box unit and servos for elevation and recoil. Likely a Barc4 and Bendini for operation system.
Im playing around with another mongrel tank to test out the barc and bendini.