Sink drain line connection...

While doing a flooring project, I have decided to re-route the drain line for the kitchen sink, while the floor is open. Currently, the drain line attaches to the main waste line with a "90". I would like to replace the "90" with a "45" sweep, to give a better angle for the run, as well as improved flow. Also plan to use a sweep at the sink end of the drain line. From looking at the pictures, would it be feasible to cut at the bottom edge of the "90", add a coupling, and then a "45" sweep? No crawl space to make a change after the flooring is installed, so now is the time. Thanks for your opinions and suggestions. David.