It's ALWAYS a good idea to get your install checked by a certified technician. 97% of parents think they are using their seats correctly, but only 20% (and IME it's been 0%) of parents actually are using it properly.
Regardless of that, I'm going to get the baby's seat checked (whatever we end up getting). It'll definitely be a seat I haven't installed before or one I've never had to install at 45 degrees. And IMO, you can never be too cautious in making sure the seat is installed correctly. After all, your child's life could depend on it.