I got the pressure cooker out and learned that it's not recommended that I use it on my glass cook top.
I processed one batch anyway but will hold off on the others until I can get an electric range with coil burners. I've got one coming in the next couple of months. I'm going to be setting up a summer canning kitchen in basement. I expect I'll really appreciate it come August.
On to the syrup. I used 1/2 lb of bark in the pressure cooker with 25 cups of water and let the steam escape for 15 minutes before closing the petcock. I let the pressure rise to 240 and kept it there for 30 minutes before removing the cooker from the stove to normalize the pressure. After an hour I opened up the petcock to release any remaining pressure. There wasn't any. I left the cooker closed overnight to cool and steep.
I removed the bark after 24 hours and then things got crazy around here and I didn't get to it for another day. After dividing the fluid into my customary 3 batches I sweetened them each to 8% as follows;
Batch A 8% sugar
Batch B 5% sugar +3% corn syrup
Batch C 5% sugar +3% honey
Cooked down to syrup as normal and voila. I have something that requires some consideration before I figure out where to go from here.
Next step was ordering some Shagbark Hickory Syrup for comparison. Hickoryworks doesn't ship to Canada but they sell there syrup through Leaman's and I was able to get some from them. After tasting I am very close.