Well the mics you have will affect the clarity. Most of these achieve percieved clarity by boosting hiend, but in fact they are quite undefined in the mids (and lows too). So if your monitoring is good, don't expect 100% satisfactory results. On the other hand you can get something passable and that's probably what you aim for.
Do you mind the sound of the mechanical noises piano makes, or you want cleaner sound? You better like the mechanical noises with uprights
. Take down all the panels you can to let it breathe let someone play the piano and listen at various places/angles. When mics are placed perpendicular to the strings, you'll get most of the fundament and as you move them upwards and angling them down, there is going to be more and more harmonics. Find your balance, it is quite important, esp with the microphones you have, they won't take EQ so well.
You can try some ORTF/NOS or modifications, but I mostly end up with AB spaced acording to the used range. It is easy to check what you're getting by playing scale from bottom to top of the range used for the particular song. Is the imaging the way you want it to be? Are all the notes in the focus? With AB there is allways some key closer to the mics and there are keys a bit out of the focus...
If you can, borrow some AKG C414 (eb or buls preferably), they are not expensive and for some reason they like pianos