It's a crutches, not a solution.
I'm using something like that now, and it's not better, because:
a) you'll have to configure each series separately (a real fun when you have more than two dozen of them);
b) groups come and go, so config file needs to be constantly updated (see above);
c) if webdl+ quality means "webdl and better", it should include amazon and netflix rips, because they are better. In this case a simple "webdl+" setting will grab those AMZN and NF rips without any additional configuration.
d) "upgrade: yes" will not download 1080p rip from amazon, if you already have 1080p webdl.
Maybe there's some way to assign quality to an entry based on regexp expression?