There are some studies on hyperhydration with creatine and glycerol.
Combining Cr and Gly is effective in reducing thermal and cardiovascular strain during exercise in the heat without negatively impacting on RE [running economy].
However I have not looked in to this further, but it is something I’m looking in to. I’m also currently on a maintenance dose of about 5g/day. My goal is a very long gran fondo in the summer. Do the potential benefits of hyper hydration outweigh the possibly very slight weight increase.