Yes the 30Q’s will fit. The Samsung is universally regarded as a very good (HKJ included) battery.
You’ll have to find it there.
Page 36 & 40 I think
If you use high modes a lot. The 30Q’s will perform better.
The discount code found in the link sent earlier the will bring the 30Q’s down to $5.00 each delivered.
They might be overkill for a stock C8 and I’m sure the oldie but goodie NCR18650B will serve you just fine.
A cautionary note though is that GB seems to be struggling service/delivery wise at the moment though I have no personal experience, good or bad, with them.
I do have experience with BG and they’ve been very good.