You do realize how powerful this fusion would be, right? A combination of Super Saiyan God and a sun dip could possibly be a multiplier in the tens of thousands, if not the hundreds of thousands. He could possibly just tank the Omega Beams at that point, if he doesn't just outrun them altogether and lead them back into Darkseid.
I like the idea, even though it would mean utter annihilation for any villain in a universal radius. Like the comments before me though, I would change the name. This current one sounds and looks to much like "Seppuku", the traditional Japanese ritual suicide.
Well, I would try combining their birth names, Kal-El and Kakarotto. It would be a little awkward and/or confusing though since they hail from two totally different cultures. Their beginning letters would also add confusion to the name.
Ex: Kakal-El, Kal-Erotto.
To be completely honest, I can't come up with a good name. Their comparisons and their contrasts make it very difficult.
Kal-Kak sounds reasonable enough, still a little awkward, but it has a nice touch. Golark is an odd name, seems being you're combining a Japanese name, "Goku", and Kal-El's American alias, "Clark Kent". To me, it sounds like some sort of ugly alien, lol. Lastly, Clokku sounds weird as well, and it makes me want to check the time each moment I hear it. I liked Kal-Kak the most though.
However, those are just my opinions, and your overall taste depends on you.
Kakar-El would be more appropriate as Kakarotto is Goku's birth name, but his human name would be something tricky to come up with, cuz in my opinion names like Goku Kent or SonClark would sound too weird.