well i have never ran a wagon so im no expert on them, but im not much of a fan of them either. but heres a pic of a fullsize wagon i watched run last summer at one of my local (1 1/2 hours away) its the green gm wagon in a full weld suiside lincoln derby.
heat 1-
lower right hand corner-
right side-
feature-
on the far side of #62
a side shot of the car *note the car closest to the camera thats a stock gm wagon rear of around the same year i think* so id say sedagoning would help alot!
he ended up winning 1st place that night sorry thats the only sedagon i have pictures of and the best ive ever seen a wagon ever fold i hope it helps