Interesting conversion Hubb.
Nearly bought the same plane early this summer for conversion but suddenly a 2x2m were on my hobbyroom instead (Propably something the cat brought in...) Planned to use an Actro 32-5 in the Epsilon on 8S4000 (already bought), but ordered an Actro 40-5 for the bigger bird instead. Waiting for matched FP EVO 5S5000 x 2 for it ... Jeti ESC.
My reason for Actro: The most experienced electro-dealer in Norway said it is among the best ones. And in addition I have read a lot of tests, also Joacim`s careful tests which claimed these motors run quite cool. So far I have not ran mine on 10S, but some 8S-testing tells me I won`t be disappointed. If not Actro I would have chosen Plettenberg...

Since the plane is kit yet then you should begin to remove weight, drilling holes and so. Look for unneccesary heavy balsa and make new parts if there are no-good things there. Have not built CA-kits so far myself, but have heard rumors some parts can be replaced/remade to save weight.

I have tried some of the Hyperion`s and except from some cogging on the smaller ones they have worked fine. Especially the 3025`s ran very balanced and strong. Found some ampere-deviation between some equals, but not too much. The 40-serie is new to me, happy if any one can tell if they are pleased with these. Then a 4045 could be a cheaper choise.