It's great to be in such good company here on the board. We have had other threads where we shared this kind of information in the past, also. You might want to search and read those to see what else may have been said that would be useful. I have fibro, chronic pain from a neck and shoulder injury and arthritis in my feet, knees, hands and neck and lower spine and hips. Medication has helped to minimize headaches which were at one time debilitating.
All of your suggestions are good, and I just want to stress that it's so important to keep doing our stretches and exercises to maintain as much range of motion as possible. Also to remember to drink lots of water each day to keep those toxins from the fibro and arthritis flushed out as much as possible. That way, we are forced to take breaks from sewing when we have to get up and go to the bathroom. LOL..
I, too, keep my ironing board in another room from my sewing machine to force me to get up and walk when I have to press. I do have a mini-iron and board next to my machine for quick pressing when doing lots of seams in a row, though. Anything long or large area, I take to the big ironing board.
Not setting deadlines is important as that adds stress and we with chronic pain need to keep our lives as free of stress as possible.