OmniSpectra
SSG? Well, I guess since he already had divinity he didn't need five righteous Saiyan's to transform. Well at least this form isn't really energy draining compared to others and the emotions are calm except for the burning fire during combat. So, He should master it much easier than his Oozaru and Evil Saiyan forms.
Author can you explain why he has SSJG instead of Rose? as far I know as long as you have a divine soul (which the MC has) instead of SSJG you get SSJR, which I think is superior to SSJG? as given that you need a divine soul to use it, it probably has a higher multiplier and theirs also the fact that it has evolution forms after it SSJR1,2,3 and 4.