I do similar work and my strategy is to work slow but make my deliverables perfect. In my experience high quality deliverables allow you to be a bit more assertive in taking control of your own schedule and enforcing expectations like I need x notice to deliver a new project, no last minute bullshit. Because remember you do high quality work not rushed garbage.

Part of managing up is showing that there are levels to this (people will tend to think they can whip up whatever training course you made in an hour and not understand the process behind it). Once you convince them there is a process then you can start to cushion it. Cushioning it sounds bad but there is a creative element that requires reflection and downtime, Picasso is not churning out a painting an hour for 8 hours per day. Then it's a matter of finding the sweet spot where they are happy with your performance but you are delivering the minimum amount necessary.