Over the years, Ken Waters has revisited and reviewed his cartridge and loadings in Handloader Magazine. I do recall that his initial workup for the 7-30 Waters cartridge was with a lever action carbine. He had a goal MV of 2700 fps, which he found he could not reach until he went to a rifle barrel of 24". As a result, when the Winchester 94AE was available in this caliber, it had a 24" bbl.
Years ago, when I had the Contender handgun in t 7-30W, I recall not getting much over 2400 fps.
I have recently acquired another Contender, in carbine form [21"] bbl. I am still in the process of fireforming brass, and so have not gotten to work up loads to Chrony. I'm not sure what MV I will reach.
All this is leading to ......if you have a choice of bbl length, you may want to consider one as long as possible up to the 24" length Ken Waters used.
In the G2, that may be the 23" length.