Matt Smith tested it and he could still hold it from the end of the handle after 15 mins (I think). This was with the light facing down. In actual use it wouldn’t get as hot and the MF05 has even more cooling fins/area. It also will have a carry handle so i don’t think heat will be an issue. I have never owned the GT myself but judging by the size of this MF05, it doesn’t seem like 100W should be an issue.
Edit: Just realised it has an extrenal fan so it should be no problem. Hopefully they can make a similar sized light to compete with the MS18.