Hi Marc,
I have not read the manual for the Vampire, but all my pictures show no flap takeoffs and full flap and speedbrake landings.
A couple of pictures from trials on a carrier! show 15-20 degree flaps for takeoff as well as one picture of the early prototype taking off with intermediate flap setting.
So for scale rotation and climb I use no flap on takeoff on the model. Should runway be a factor, you have the option of selecting approx. 15 deg flap for a shorter takeoff distance. I use this on grass as well to get airborne at lower speed.

As for landings with full flaps and speedbrakes, this is a LOT of drag and you must of course be prepared for relatively high power settings on final. You are better off in case of a missed approach as the turbine is already spooled up, even if you should forget to retract speedbrake and flaps. We are close to 1:1 trust to weight and the model will climb nicely even in a dirty configuration.

In gusty wind I normally reduce flaps to my intermediate setting to obtain better penetration on landings.

I agree with Kerry in that 60 degr. flap is enough for landing, but 80 degr. is scale!

A couple of details of gear doors, speedbrake and flaps.