I'm talking about actually practicing landing in a field (without actually landing of course)
Here in lies the point of my post. To have the benefit of practicing a power off approach and landing, you have to land. Getting to within 200 feet AGL of the ground and powering away saying that you could have completed a landing is only a part of the training, and not the most valuable part. For the time when the engine has actually stopped, things may be different, so lots of practice is your friend then.
Flying the "best glide" speed accurately to short final is a demonstration of precision on your part, but may not set you up for your most successful landing. "Best glide" speed is the speed which provides the greatest distance per altitude lost (I'm sure the the sailplane pilots in the group can comment this better than I). Flying that slow speed will not give you the best excess to out maneuver wires seen late, or stretch 50 feet over a fence. Your practice may show you that carrying extra speed on the final 200 feet, to the flare provides you extra flexibility in your landing, and is easily slipped off if not needed.
If you happen to have a large airport, quiet at the time you are there, ask for a EFATO practice, and pull the power on yourself a hundred feet up. BUT CAUTION! Set yourself up well, with some extra speed before hand, until you get use to the maneuver! Climbing out with some flap extended, at Vx, and chopping the power at 100 feet, is a certain recipe for a very hard landing. The most scary flying I have ever flown was slower Vx EFATO testing in a Cessna Grand Caravan from 50 feet - I thought I was going to wreck it for sure. The testing requirement of 80 KIAS rather than Cessna's 87KIAS climb speed made all the difference, and the EFATO at 50 feet requirement (safe landing) could no longer be met.
When I mentor PFA's, every one will be set up for an actual landing (could be touch and go) to the surface. To assure that I could complete the PFA I have set up, I will always set it up so a slip is probably needed to get in nicely. If I'm going to do a power off landing, I'm not going on an un-necessary cross country, if there is a suitable field below me, that's where I'm going.