Yeah, 300mg is a fairly moderate dose so I can't imagine you'd need a lot of Adex on cycle so that's fine. Just be wary that by the time you can feel sides things may have gotten farther than you want them to be but as I said, I think you're okay on 300 a week.
Start your PCT/SERM 10-14 days after your last pin of test E, it's a long ester and will take 10-14 days for the test to clear your system. The test must be out of your system before recovery can begin.
It will probably be as important as ever to take your AI in PCT. Just taper off the dosage so 0.5 eod then after two weeks move to e3d then continue a couple of weeks past the end of your SERM.