Congrats Harpgirl. You may or may not know from past posts, that I've devised 'removable chord cartridges' for my regular tuned harp, but the one I play the most is definitely tuned for F (and C)
I use a maximum of seven bars in order to give more 'playing space, and currently my F harp has F,Bb,C,G7,C7,Gm and Dm. If I'm playing a song in C, and need an Am, I take out the Gm and replace it with Am.
F is a wonderful key for tunes (great midrange) and suits my (baritone) voice for old time songs that I might normally do in the higher key of G on guitar or banjo.
There are of course "correct" keys for virtually all dance tunes, and these are the keys that the fiddlers use, and yes, they'll get snotty when you change them. That's probably why it's a good idea to carry a spare harp with all the majors and minors for the keys of G, A, C, and D. At least that way you can chord along. But by all means, work out your complex tunes in F. They'll sound great.