These are all great tips and a few I will translate into my next attempt:
1) Pre-hydrate - that was a fail as I poorly estimated the importance.
2) Planning - I didn't actually include planned stops, just assumed I would find some along the way
3) Slosh is good - I don't feel like I ever reached slosh, so even all that I consumed, I must have sweat more out
4) Ice on Body - I debated this as even pouring warm bottle water over my head was cooling, so using some to pour over me would be good