Heya it was great to see ankle Biter at the eruros!
Most beetle competitions now impose a 250mph tip speed limit (im pretty sure the euros was 250mph aswell). If the base plate is not a structural component then 1mm 7075 would be okay to hold in the electronics but dont expect it to to stop a spinner in the slightest.
So I use that exact weapon motor in Let the good times roll on 4s. I run it on an afro 30a and only killed itself during the limpet fight when limpets tyre got wrapped round the drum and i was trying to spin up the drum to dislodge it. The afro melts its plastic coating every fight but seems to run okay although the longest it ran for was 2.30 mins not the full 3, bear in mind the drum I use is 540g and that beater looks a bit lighter aswell. I was thinking about upgrading to a 40a esc but apart from the limpet fight which was just unlucky I havnt had problems with the Afro 30a.
I had driving problems with mine first off, shortening the entire frame by about a centimetre and a half and reducing the friction at the front worked for me but i cant say for sure how your robot would drive in either configuration.