for a $350 per hour provider who you had a good time with and plan on repeating?

and tips are hardly obligatory, BUT if you really want to show your appreciation for a great time, I would say that between $50-100 is more than enough to say "job well done"

Personally anything less than fifty bucks seems to me at least like a waste of energy, and unless I ran way over on time I really can't imagine giving a tip of over a hundred.

There is of course no cut and fast rule for this type of thing. I am sure everyone will have their own standards.

... it honestly depends on the individual lady and I just happen to be pretty easy to please lol.
The most modest tip I've been given was a $5 Safeway gift card (grocery store chain) plus an add'l $10 in cash from one client and I was still pleased as a peach. But then my biggest so far from another client gave me an add'l $300 in cash plus some gifts worth an equal amount to the cash tip and I was very thankful.  

Providers consider themselves professionals and feel a tip is out of place, just as it would be out of place to tip a doctor, lawyer, dentist or any other professional. Some might not feel that way. A gift like fruit, a book, wine, whatever is a different matter. I'm one of those people who feels a bit uncomfortable showing up empty-handed whenever I go to meet someone "socially," and it depends whether or not you consider a session a social encounter as well as a strictly business appointment.

No tip is ever necessary or expected of course. I mean I've received the gamut from flowers to handwritten cards, to bottles of premium liquor, to expensive hosiery, lingerie and jewelry. I'll even admit lightbulbs and extension chords (don't ask). While it's the thought that counts, we are here to bring home what we can at the end of the day in terms of cash. I've appreciated all the gifts and the thought behind them, but the cash gifts are best adopted. Which can also mean a repeat appnt.  

Guys, feel free to throw extra cash at me anytime. I assure you, there will be no offense taken.  

...that ends the business part of this for me (other than leaving the envelope of course).
After that, I like to leave money completely out of it (and damn, the amounts I'm paying are already going to force me to delay retirement until I'm 80 lol!).  I left tips on my first two dates, but none since.  Does somehow seem just a bit crass to me - but I know everyone doesn't feel that way.  But I do often bring a small token gift with me, to show respect and get the date started with a good vibe.  Treating a lady with respect and providing repeat business are the ways I show appreciation.  I'm usualy greeted with the warmest of smiles for second dates, so I don't think anyone has been too "offended" (yes, slight sarcasm) by a lack of tip.  Fuck, I'm never going to be the biggest $$$ guy around anyway, so there is no point to faking it and throwing around money I really can't afford to anyway!

but that doesn't mean that there aren't some REALLY DUMB answers. lol

+10.