Hi Turbocharge
400ft is plenty. Even my "hot" landings don't take more than 200 ft! You can slow it down, but this must be done on the downwind leg. If you can get a nose up attitude under power on this leg, you've got it made. Practice makes perfect! Remember the turbine lag if you running a bit short. Does not get worse than a bounce if you get it wrong - bent undercart.
How much fuel are you carrying? I have got 3 litre on board and that gives a good 8 minutes with lots to spare.
RAM 1000 will be perfect to get you off, thereafter you won't need much more than half throttle!
Regards
Zane