You can stiffen the tracking to any kayak by adding a keel strip to the stern. It would be made of hardwood and 1/2"wide about 2 1/2 - 3 feet long that tapers from nothing to about 1/2". The water side of it would have a gentle round-over shape.

Use an electric glue gun to fasten it to the kayak for your trials. You can shave it down for experiments. Once you have the one you like, you can do a permanent installation.

I actually did this on a skin boat that was all over the place on me and it worked out well.