Supercars - commission for introducing seller and buyer?

[PhillT]

Hello all,
I have a query for those in the know.
A chap recently contacted me asking if I could help him track down a buyer for a supercar owner that he represents. The car in question is serious money - well into six figures and not far off seven.
I put the word out and found someone representing a couple of interested collectors. I've been acting as a go between since then.
The potential buyer's representative does this regularly as part of his business and has sent me a commission agreement to pass on for his part in the deal - 3.5 percent of the total cost of the car, which the seller has agreed to.
Now, should I be considering doing something similar? This chap stands to make a decent amount of cash thanks to a deal that I've set up, but he does this kind of thing for a living and I'm in uncharted territory here, having never done this before.
I don't want to appear greedy, but on the other hand I don't want to miss out on reasonably benefitting from an arrangement that I've facilitated.
What do you think? Would it be completely out of order to ask for a gesture of thanks for setting the two parties up, and if so how should I go about it? What's reasonable in terms of percentages etc?
Or am I simply being a moneygrabber that would be morally better off putting the two in touch and wishing them well?
I await the PH judgement.

Cheers.

Edited by PhillT on Monday 8th November 13:39

[dvs_dave]

I reckon asking for 0.5% finders fee/commission isn't unreasonable, as without you your car dealer mate wouldn't be getting any of his 3.5%.