simcha:
1. Try it in the form of money. It is very well deserved by the shadchanim. I think you miss the point. It’s not about hakaros hatov any more than compensating your plumber, contractor, or hair dresser is about hakaras hatov. They don’t want to be treated like chesed cases, they want to be treated like they deserve to be treated for their time and effort on behalf of singles.
2. If you feel uncomfortable calling yourself (understood) get a bit creative and have a friend call the shadchan discuss you and present it as if she (your friend) is willing to compensate the shadchan for her time and effort every time you reach a date #2/date #4. This way it’s not uncomfortable for you or for the shadchan and it yields the result that you are looking for.
3. Being that this is a public forum i would suggest many many people do it for their friends. It’s a simple effective way to help their friends get attention. It’s something married girls could do for their single friends. it’s something a class could team up and have all the marrieds pool some money and help all the single from their class. A small amount of money will go a long way.
Here’s some simple math. Suppose 70 girls in a grade 20 still single. if the 50 marrieds kick in on average 250 for their classmates, and the offer is 100 for a date #2 and 350 for a date #4 there would be enough money for the 20 single girls to reach date #2’s 125 times or date #4’s 35 times or some combo of the two.
You get the picture. It really really works.