The Seattle extension, in particular, is seen as the current favorite. This years's NACMCC saw more past champions registering in the Seattle division than any other.
For this reason, I highly recommend players brush up on their awareness of forfeiture rules. All of the top British strategy guides include a relevant appendix in their latest editions, I'm particularly partial to Banks, et. al.
Banks et al. was historical curiosity. But over the duckpond it seems to be canon! Meanwhile Carruthers vol 6 is openly disregarded.
A clash of cultures for sure.
"But how is a duck pond a duck pond if there aren't any ducks."
The elimination of trackage limits when influenced by bi-directional Perridale has been pretty mainstream now for a couple of years. I’d hardly call them “fringe” anymore.
Agree on the need for sufficient awareness of forfeiture rules in general though.
Personally I’m warming towards the proposed Eton’s Lisp amendment which does seem to improve some of the issues with deadlocked rounds, especially with larger numbers of players.