Doc,
not to be a kill joy but over on RC Groups in the EDF fourms
there has been a few threads on the Ramtec and many on the Dyn-e-max...

it's seems that the higer pitch of the Ramtec makes it really draw high amps... where did you get those? are the home brewed of from retailer?

For this project if it was me I'd only run the Stu Max or the TJ-100
not that the Dyn-e-max of the turbax aren't good fans ... but with the extra weight of a twin and the higher amps draws of those fans you flight will suffer

I really don't think you will be happy with those fans in this nice plane.. I'd guess a 3:00 flight on 5000mah packs with those fans drawing up close to 120 amps
The Dyn-E-MAx does much better with this motor pulling around 95 amps and 4400 watts

Ron