Hey Signmaker,
Here's what I get...
Deck (510) to top of ring: 41.4mm (1.63")
I hold it in my hand, with my trigger finger on the button (so if you pointed the atty driptip like the barrel of a nerf gun you're pulling the trigger to "fire")
I hold the VTR with my thumb on the button, same position of the hand.
I haven't swapped out the firing button, because I like the knurled locking ring on the one it ships with.
The battery placement is just as quick as with the VTR, if you unscrew the button (which is easy) and drop the battery in that way, the VTR bottom hinged/spring loaded door can be finicky a times to snap shut.
Of course you need to grind off the ring on the VTR after taking it apart to get things like the kayfun size tanks on it, major hassle, but worth it.
I like the VTR as my all day out and about pocketable mod. But honestly, the Square box (clone I have) is lighter, less of a fingerprint magnet on the sides (I have the silver VTR), and fits in the hand a little better. I'm using it now as my pocket vape.
I've been running just 18650 in it for full mech unregulated mode, and using a kick dropped in with an 18500 for regulated.
What's this about water survivability? You mean nothing shorts out or fries (electronics wise) when it gets dunked? I guess that's true of any full mech mod.
I've dropped a dripper on it, but without a long drip-tip to clear the ring, it's a bit unusable. Whereas the VTR with ring ground off is just funny looking with a small dripper on it.
Here's a shot of both side by side with a Kayfun tank in each.