Hi Welcome to ECF Zen, I have a VTR, had it nearly 3 months now. I would start any new tank on 8w and work up from there, I'm vaping my 30s at 10w and getting a nice hit from it. I think I tried around 13 once but nearly burnt my lip.
The aerotank non mega version fits ok and is a nice vape with its adjustable airflow.
Oh best advice would be: Be very careful with the threads the 510 connection is a brass mix and most tanks have stainless threads, so they tend to eat the brass like its going out of fasion. There are a lot of knackered VTR's out there with stripped threads. As Bilbo who will probably be on this post later will testify too.
Get a stainless 510 to 510 airflow control valve $3 as soon as possible and screw it down tight so it wont unscrew when you take your tank off and you will have piece of mind.
Here is what they look like on.
Best £3 Ive spent.
P.S don't get the kanger airflow control. That one is meant to go on the base of a protank so is not 510-510