Coming from operating nearly/full a/c pretty much every flight most of the time the de-rate, asum. temp methods to be honest didn't save us a lot but yes we still did it when poss.
As for windshear reported i personally would be straight to full thrust t/o there is no second chance windshear is a variable beast and just cause the guy before got out doesn't mean you will. As you said yourself your gonna look fairly silly at any AAIB hearing if your saying yeah i knew there was windshear but i thought we'd get away with it. Fairly sure even the harshest of CP's couldn't really argue with that logic.