I've had great success with the DNA method, and on some rather crack prone fruit wood, like cherry. I've only lost a bowl or two, and those were really questionable to start with.
I use a 5 gallon plastic bucket I got from Costco, that held laundry detergent, I use the standard lid, which is NOT airtight, but close enough. I'm in need a new tub of DNA, as more than half of mine has evaporated, and been lost to soaking into the blanks. As I have a DVR, I don't often get many pieces off my lathe that will not fit into a 5 gallon bucket.
I think worrying about evaporation is not worth your time, It think you will lose a lot more DNA soaking into the blanks and then evaporating during the drying process, which is what is supposed to happen
When you wrap the bowls after they are removed from the DNA bath, I'd really take care in wrapping them, thick brown paper, and a good tight wrap.
If you look at >> this thread << you can see what I do, I know some think it is overkill, but like I said, I've not lost any bowls that were not iffy going in (ones with large inclusions etc).
I hope this helps, and I hope some other turners in your area chime in.
The pessimist complains about the wind; the optimist expects it to change; the realist adjusts the sails.
William Arthur Ward