Brass Monkeys courses are quite a lot longer than the Gorrick XC races, usually 7-8 miles as opposed to 3-4 miles.
Generally they are in locations that drain well and therefore don’t get particularly muddy, but heavy rain immediately before an event will mean mud and slop in places. Gorrick/Brass Monkey courses tend to be better than almost anywhere else that doesn’t have a rocky base in the case of inclement conditions. Be mindful that if it is wet, a lot of the terrain is quite sandy and you can easily go through a set(s) of brake pads.
Most people don’t do practice laps for these longer races due to the extra course length.
The course locations do change from year to year, and even at the same venues sections or even the entire route may be ridden in a different direction. However I have found Ash Ranges the least rewarding of the venues in the past, but since the last event there they may have added extra trails in there to make it more engaging.