About the 190 F seat, I can't find anything either.
Though not what you were looking for, what about the cloth belts? My only reservation in suggesting this product is I've seen it mentioned that people had problems fitting the belts through the metal pieces - maybe this is just HGW product?
There is build review here, and they used RBproductions and I did not notice them stating any problems putting the belts together:
http://forum.largescaleplanes.com/index.php?showtopic=56578
regards,
Jack