2000-1000
I have done quite a few now, with both my RV's and have found these numbers:
High key 2000 AGL
Low key 1000 AGL
I aim for 1500 AGL midway beetween high and low key, and 500 AGL on base.
These numbers gives me a margin so I can compensate for winds during the ELP.
I initially aim for 1/3 down to RWY and when landing is assured, (usually on base) I move the aimpont to the T/D point by lowering more flaps and sideslip alittle if neccesary.
I let the engine run at idle, and the C/S prop fully fwd.
To compensate for the idling engine, I set t/o flaps when entering hight key. ( I fly the pattern at 75 KIAS)
I've found that the glide-distance increases quite alot with the C/S prop set to coarse. (20-30%)
However, I don't want to do practice ELP's with the prop that way.
Therefore I have the coarse-option as an emergency "strech-the-glide option" schould I need it.
During practice, I train on intercepting the ELP pattern anywhere during the 360 turn, just in case I won't be able to start at 2000' AGL directly overhead a planned landing site in an actual engine failure.
BTW: I always plan to do the ELP as a full stop landing. This is because the engine is cooled rather much during the ELP and I don't want to add full power on a cold engine to do a t & go afterwards.
This is specially true during winter time ofcourse.
(yes, I know I baby the engine, but it's MY engine...
)
You dind't mention if you have a FP or CS prop? Since the glidedistance is pretty different on those two, the corresponding numbers will probably vary quite alot... you schould find the numbers for your aircraft. It's pretty easy and fun too!