I often get the best results by miking the harp from the front, removing the kickboard first. I'd highly recommend having the piano professionally tuned before you recording it; it's well worth the investment. Also, check the pedals and see if they might need a little lube to keep them from squeaking too much. And finally, pull one side of the piano away from the wall a little so that there's at least a good 15-20° angle between the piano and the rear wall. This will help curb standing waves which can mess withthe sound of the piano.
As far as mic selection, I've found that no two uprights in no two rooms take to microphones the same way. My best recommendation is to expiriment with what you have and see what works for your situation; but go for something in general that gives you a decent full-range balance on the left side and the right amount of brightness for your desires on the right side. One mic each side (they don't have to be matched, IMHO), under the keyboard and facing in on a short angle towards the harp. Give the player enough room for their legs, of course, but other than that, distance L/R for best balance maybe about a foot off the harp.
An alternative, sometimes you can get a decent sound of the back of the piano. Similar miking technique, except your miking the back of the soundbar instead the front of the harp. This tends to work best when the piano is not against a wall.
Personally, I rarely care for the sound of dropping mics in from the top as much as the above options, and only use that when the other methods are not options.
G.
