Before the reverb, personally. However you can get some awesome sounds with OTT after reverbs as it brings all to the front of the mix.

Depends in the context of the track. Is the piano playing in a breakdown or in a busy mix? That will affect your mixing decisions. If your going for a 'vintage' sound I'd go for a band pass sound and cut the highs and lows to thin it out. A lot of old vintage sounds don't have the top end of modern ...