A CE2 is a viable option for you.
I use them with vg with a very simple
mod. I just snipped the inner seal slots a little bigger, into /\ shapes. I had to because I use VG so you may not need to if you're a pg vaper.
I've tried out the g4s before and I thought they were a world apart from what a CE2 can do with "similar" design.
The one drawback for the CE2 is the casing is prone to cracking, easily. However, the ultimate edition (only on the small size for now I think) are very sturdy. For the XL size (also called fluxomisers I think?) you can get a BD 3ml syringe and cut it to size and it fits, perfectly. I don't know if they have an ultimate edition for the XL sizes yet. My partner accidentally ran one of my CE2s over with his car, it cracked the syringe case I made for it but the CE2 guts inside were undamaged and worked perfectly with a new case, so they can take a bit of a bashing.
Metal cased CE2s exist somewhere but I don't think it's a requirement if you get the smaller CE2 version with the improved casing, or
buy a few very cheap syringes and cut them to size for the larger sized ones.
I love my CE2s and wouldn't have a viable portable solution without these things. Worth a look in.
CE3's exist but I'm pretty sure they're similar to the G4, just with a weird cork thing on them. They're also called smokeymisers (?). I prefer the CE2 over these because the coil is at the top and they'll actually wick VG, even my thickest vg liquids with a very simple modification. The g4 and ce3 can't do this.