When I'm coaching people I like to have them experience and become confident with flying at the bottom edge of the flight envelope before getting near the ground.
I prefer learners to be able to identify, predict and automatically recover from stalls before letting them get cocky near the ground... I have them flying as slow as they can, at height, pulling tight turns and getting used to "feeling" the aeroplane near the stall - low speed, nose high attitudes, mushy controls etc.
I'm very old school though and I built all my own models and thus it was a big deal to crash them, so I tried my hardest to avoid unneccessary destruction. I still do it now with new models - I take off, trim out, then go up high and stall it clean, dirty, straight, in a turn, power on/off etc etc. That way if the engine dies on me during the rest of the test flight I am at least familiar with the aeroplanes limitations and give myself the best chance of a successful landing. Again, this is me trying to preserve a big warbird I've spend a few years building from a plan.
Ultimately, stick with your instructor as he'll know when you're ready. RCKen's technique of announcing the landing at the last minute is great - no time to panic
As for Corsairs and Mustangs - lovely aeroplanes. I started as a teenager and thought I'd cope. I built a couple of fairly hot scale models - and smashed them all sooner or later. It was nothing short of heart breaking. Looking back it was all wasted effort and those models would still be here now if only I'd got more experience first.
To me, training to fly these awesome scale models is more than just having a high and low wing trainer under your belt - it's about getting a good few years experience of just flying in general. It takes time to see what the gremlins will throw at you, from engine failures to radio failures etc. That experience is something money can't buy - and it's gutwrenching to learn the hard way using your pride and joy.
Also - building. So many people try their best to make a decent go of a kit or plans built model, but inexperience of building leads of silly mistakes that simply frustrate, spoil expensive models and makes any consciencious budding modeller kick themselves.
So, sincerely, if you really want to learn to fly, and your ultimate aim (as mine was and still is) to fly hugely rewarding scale models of WW2 fighters - build yourself a few low wing sport models. From kits and plans ideally.
ARTF is great to get you in the air, but you learn nothing about construction and the learning curve on the Corsair will almost certainly be too much for most. If nothing else it'll be untidy and unslightly. And probably covered with Profilm. No offence - but there's nothing worse than seeing a big warbird covered in iron on films [:'(]
A SIG 4*60 or even an Astrohog if you like the classic look would be brilliant - or have a browse through plans retailers and pick something simple. It wont take
that much longer to build a simple box fuselage low wing sport model from balsa, ply and a set of plans than it would to assemble an ARTF - since most of the worst bit is all the fiddly bits like fitting radio gear etc.
It's really rewarding building your own, and it will develop skills with a scalpel, razor saw, razor plane and sanding block that will DEFINATELY make your life sooooo much easier when you build your Corsair.
Bit of a long term plan, I know - but there you go

One last point - many people will criticise older models such as the Astrohog because they have certain characteristics which make them fly less than perfectly. An Astrohog, won't for example, flatter you with knife edge flight in the same way modern ARTF aerobatic models will. IMHO, those "mannerisms" are
exactly what you need when you're learning to fly warbirds - because warbirds do not fly perfect - far from it - they have characteristics, mannerisms and bad habits by the bucket load. If you're used to flying planes which have little quirks like these - you stand a much better chance of success with aircraft like the Corsair