I think GRCS is 5/8 max rope dia and 3 wraps rope.
The bottom of the spool isn't flat and curved ... doing what you do will get bunching, I believe the Hobbs is this instance would be the better choice, long flat spool.
Also, dang you guys are cutting some big wood then.
5/8 double braid is good for around 16,000lb breaking, gives you 1,600lb safe working over there.