Ice slurries can temporarily lower a person's core temperature and increase stay time in heat stress environment., That is wrong, in fact the complete opposite is true. Think of the body like a car engine. In the cold the enginge regulates its core temperature by shutting off flow to the radiatoras the temperature increases the flow through the radiator increases to cool it down. In the body, blood vessels in the skin act as our radiator contracting and expanding as temperature dictates. In cool coditions less blood flows through our radiator to preserve our core temperature.
OK, so you have been cycling, you stop and have a cold drink or ice cream to cool yourself down but what is really happeneing? The body reacts the same as you do in the evening - it is getting cooler so you shut the windows and doors so the body limits circulation to the skin preserving core temperature. Why do you think we Britisn drank tea in India and not iced beer?
The OP mentions keeping clothes wet - I will need a water bowser behind me and a continual shower. I can be completey soaked and a few minutes later I am bone dry (self+clothing)
he also writes about electrolyte balance. Try using Oral Rehydration Salts - normally sold in small sachets for diarrhoes suffers or (ypu will have to pre prepare this) alarge bottle of lemonade/7-up/Sprite, take the cap off and allow to go completely flat then add a teaspoon of salt. Do not add salt to active lemonade, you will be wiping it off the ceiling!
Do not cycle for more than one hour at atime, rest frequently and take plenty of fluids. Bananas are good for you by replacing lost potassiom.