I live in Michigan and have hot water radiant in-floor heat in my 28' x 36' shop. When I'm not intending to be in the shop for any length of time, such as generally weekdays, I keep the heat at 55 degree (F). Most weekday evenings, especially in the winter, I'm not out in the shop for more than an hour to 90 minutes per day, some evenings not at all, so I don't change it... I can get by at 55 degrees. Though for me personally, 55 is a bit on the cool side, depending on what I'm doing.
On weekends, the pattern may be different.
If my plan is to spend "quality" time in the shop, such as most of the day, which is common on Saturdays especially, I'll typically turn the heat up to 60 degrees first thing in the morning when I go out to do the chores (we have a small hobby farm with animals so I'm out early). I then go in and have my morning coffee, check in on my email and favorite web sites and such, and by the time I get back out to the shop, it's getting about where I want it to be for the day. If my intent is to quality time in the shop on Sunday, I'll maybe drop the heat to 57/58 degrees, and repeat the process on Sunday AM. Then again, I might just leave it at 60 until I'm done in the shop on Sunday.
If I'm not intending to spend more than two hours or so in the shop on either day of the weekend, I don't change the thermostat.
There's no particular reason I worked out this pattern, but it seems to work well for me.