I got my Score already assembled and modified by Crist Rigotti. I had the nose fall off mine in mid flight at Oshkosh a few years ago. All the slot and tab joints just came apart. The hot melt glue is the problem. I could peel it off like rubber cement. I cleaned off all I coul, re-assembled using C/A glue and epoxy along with an extra gusset or two here and there. Then I coated the whole works with brushed on thinned epoxy to fuel proof. Mine has a Saito .56 in it using the stock R/C type mounts. I have no problem with this style of mounting. If it makes it easier for you to put together, just try and pick and peel as much of the original glue off as you can. Then flow thin C/A where ever you can. When finished there and if it seems nice and solid, then coat the whole thing with thinned epoxy. I noticed flying mine after the repair, that I could feel engine vibrations down the line at the handle, quite normal for a large model, and I never did before. That's how rubbery and "loosie goosie" the front end was before it fell apart. As for engine, use whatever you desire. Flip a coin if necessary. That is one advantage of the R/C type engine mount, you can always easily change out the engine. I would go for as much power as possible. Mine weighs 72 ounces, but flies better than I can fly it, and it carries the weight very well. I have an extra one put away that is missing parts that I bought just for the wing. Very nice airfoil, whatever it is.
Good luck and have fun,
Dan McEntee