JR R610 recievers-problems/success
I have seen several folks use electric Helicopter speed controllers in airplane applications that need a lot of power.
I don't really know how big your aircraft is, or how much wieght would be a problem.
JR makes a good, reliable, rock solid speed controller for 30 size helicopers but it is a bit expensive. It is also big and heavy.
You might find a more suitable one made by another brand.
It is probably cheaper just to change receivers. I would go with the R700.
Another angle you might try is to find a hobby shop that will let you try different speed controllers with your receiver in the store.
If you have not already, you might try asking these questions in the electric/park flyer forum. Those modelers will know much more about speed controllers than I and most of us in here that only fly Nitro and Gas.