The GT4 will have far better thermal properties then either of those lights, on turbo though it will of course still get hot enough to need to step down, that is expected with a ~300w light.
We are trying to get them to make a handle for the GT4 to make it easier to hold and it keeps your hand away from the light itself, so you could disable the thermal protection and it would not burn you if you desired (the light itself should be fine but will need to test to make sure).
It WILL be heavy though, that much is known for sure.
have you seen how beefy the head looks? its made for this type of emitters to absorb that amounts of heats those emitters will produce, doubt they have plans for anything else, but that depends if enough demand they might produce something after but dont count on it for now maybe…
There are no plans for other emitters at this time but the design is such that DIY mods should not be hard. You could use 3v, 6v, or 12v LED’s without much trouble. You would just need large ~26mm+ mcpcb’s for them.
An XHP35 version was considered but honestly you might as well just get the GT70 as I expect that the throw and output would be similar. The only benefit would be better tint options but that is not enough for most people.
A boost HX version would be interesting to consider once the LED is released but till then it is impossible to say if it would be worth it.