I've been thinking about the same thing. The question I've been thinking about a

Is there a newer spread sheet available to compare the polars of these gliders over the speed range? Here's an older link to one with some of these gliders
https://www.gliding.com.au/assets/docs/Polar10.xls

I'm a bit uncomfortable with the dynamics of the skinny tail boom. They don't always seem to stay attached. How careful do you have to be with them?

Which of these gliders are competitive at 18M? I have a glider with 15 and 17.6M tips. The big tips seem like reverse water ballast. They let you go slower (less sink) which is great for just hanging out in lite conditions.. In strong conditions, the wing structures to not permit enough water to make them faster than 15M. On the other hand, the lighter wings are really easy to assemble.

On good weather weekdays when there isn't a tow pilot, the idea of a motor is on the table. Is the permanent ballast and maintenance story worth it?

Good luck with your quest.