Rear wipe not a big deal for me, rarely used them in any of my SUVs. The way the roof is pitched I think prevents the shade in the C40. I plan on doing as dark if tint as possible. Probably going to do same on my XC40 since enough heat makes it through.
I’ll probably end up doing the same when I get my front tinted minus the windshield. However I do like to take advantage of the sun for example my V60 shade is always close except for the winter and then it’s always open to allow the sun to warm at the cabin at all times when possible.