If you can tell the difference between the green squares and the red triangles and keep your boat between them you chould have no problem following the ICW anywhere.
Don't laugh there are plenty of boaters out there who can't. Never assume how wide the channel is . don't ever cut corners or swing wide. go strictly pole to pole and watch every minute. Never assume the boat in front of you knows where she is going. and if in doubt slow down!
I always here a lot of complaints about the position of the markers, but 99 times out of 100 a careful watch shows it is operator error.