Measure once, cut twice!.... Or the other way round...
That's the joys of fabrication, something thought to easy can become a pain and other things that look difficult can be easy to make... I always use the CAD (Cardboard Aided Design) method before I print it to steel . With the baffle the easiest way is to cut it back at one end and attach to the other... Or make up an angle for it to sit on at the short end, just ideas..