Hi Lex,
Many folks use that meter--however it doesn't count amp-hours.
Watt meterI don't see the point of a Victron or Trimetric.
It may be better to use a Kiss principle when designing a solar system.
It is always better to have too much capacity than not enough. Full timer's need far more capacity than part time folks.
Wire size is determined by the kind of controller. The kind of controller is determined by the raw voltage of the panels. High voltage panels are significantly cheaper than nominal 12 volt panels (which are, in point of fact, 17 volts and up). Once you reach a panel voltage of over 21 it becomes prudent to go to an MPPT controller.
I full time and I run mostly on electric power (water heating, fridge, and cooking). Therefore I need a large solar system.
When I did NOT full time, my existing solar system was more than adequate for a seven to ten day trip.
Running a generator is more expensive than going to an inexpensive campground. Solar is a one time cost.