I agree this was the idea, easy change from one engine type to next one by using the plates, which have engine specific hole pattern, but always same holes for the hardwood bolting. I found today a set of the MK floating mount in my other Aurora kit ()

Since I am no way intending to change every other week the engine in my Aurora, I have installed the plates permanently now. After some more consideration, I will not tap threads into the Al plates and wood as it may be too weak for safe tightening, as Will remarked. The aluminum may be too soft, and the thread size is too small for being well tapping in wood. Instead I will use self tapping wood screws to bolt the Hanno down.

I am curious how the Aurora will handle with the Hanno special - if it does so well as it looks, it will be outstanding!