The reason I don't post about doing 100's is because when I give suggestions to newbies doing thier first or second 100, I basically have been told they don't want anymore advice, thank you. So I have kept fairly quiet.
However, The best thing I found for doing 100's in is a silk sleeveless blouse. Kept me warm in the AM under polar fleece and cool in the PM when it warmed up. Only problem was the horse likes to itch on me and the blouse suffered. Also, I like a COMPETE change from the waist down at the 1/2 way point and another pair of socks at the 78 mile point. ( I got that from Valerie. See, we listen and watch!!)
I am not always at the front, only sometimes. It depends on the day, the horse and the training.
Becke in MI who will do 100 next year with 3 juniors.