Just caught your post, and hope that newer PT37/40 owners will respond.
The older PT37's have a different boat deck construction and underneath area to span, so there isn't any meaningful comparison with tender weight on your boat. In addition, some boats did not come with factory mast/boom configurations, hoist systems may have been added later. I don't recall how your boat was configured when new.
Having said that, WESTERLY has a tender that weighs in at around 600 lbs, with a similarly rated low profile davit. It is a good system, but I wouldn't want to see any more weight on the boat deck. I don't see any of the newer PT37/40's with this kind of weight, max is probably around 3-400 lbs.
Of course, the main question you need to answer is how much bigger a tender will fit your needs?
For us, a 4.0 meter RIB with a 30HP outboard satisfies our needs to explore and fish. But maybe you only need something to take the dog ashore on occasion.
There are obviously a lot of choices, but try to pin down the desired type and size, then refit your hoist system, if needed.