To answer the actual question at hand, I would never blatantly solicit (PM/email/call) business from gents on boards or even previous patrons. That's what ad's & website updates are for.
The only way I'd ever think to contact a gentleman to let him know I'm available is if he is a consistent LTR & even then, it would feel slightly intrusive to me. If a guy wants to meet with me, he'll contact me with his availability. If he's an LTR, in my experience, you get to where you have a regular schedule with each other & know you're going to see that person once a week or whatever.
My 2 cent's.