No thank you to the cotton canvas tents, fine on the continent in dry warm weather but nah not for UK use.
Space is in short supply in the car with paddle boards and other stuff, that’s why I was looking at mountaineering tents, its the size more than weight which will be the issue. Big family tents are still big when packed away.
I used to work in a camping shop in my teens so know a little about what design is good and bad. I still have memories of families coming in after a rough night with shattered fibreglass poles and miserable faces after sleeping a family of 4 in a car because the tent collapsed. I want to avoid this at all costs!
There is only 2 of us so 3-4 would be plenty big enough. Inner or outer pitch first makes no difference to me. Pros and cons to both.