What is your definition of "transaction based?"
Specifically, what is your client: a RE broker, RE agent, mortgage broker, mortgage banker, title agent, etc.??
This is one area where it pays to be very specific in your description of risk/exposure.
Frankly, the GenStar program is good but it is onerus and an administrative pain in the neck. One thing that has always bothered me about it is if you have a builder who sets up a real estate pup to sell their own properties you have no coverage. Now, I don't know how that plays in, say, Iowa but in CA its can be a killer.
"Free" ain't free