Well, I have a Zagi THL that I added a towhook to--and it DOES launch ok with a small hi-start.
It flat land thermals too, have even hand-launched it into thermal flight,...but as I said before, if a thermal type plane is what you REALLY want, there are better choices.

I guess what I am trying to say is this...are the 'flying wing' type gliders high performance thermaling machines?..NO!
CAN they thermal..YES!
Are they fun and challenging?...YES!
Will they do what YOU want?..I don't know....it DEPENDS!!
If you want a hi-starting thermal machine, I believe you need something else, (just ask here, you will get LOTS of opinions!).

But..try a wing anyway, never know, you may get hooked!
Pud