At SKW we have historically been able to drop down to min, which is now 58 credit hours, during slow periods. Even if they don't have a lot of reserves, there's usually somebody who needs/wants money and will pick it up. When things get VERY busy (like this summer) everybody is maxed out and burned out so you may not be able to drop anything unless it's really sweet.

You can drop below 58 if you use sick or vacation time, but they have fixed training and benefit costs so they won't let you drop down to 20 hours/month. If everybody did that they would have to hire 9,000 pilots.

You can always do unlimited trading with open time and other pilots, as long as you don't drop below your original award credit.