Interesting approach to making the sauce but I think you’ve unnecessarily added an hour to the process. All of the steps you take in preparing the sauce are the ones you’ll find in any blender style béarnaise sauce. The hour for the eggs and butter is overkill as you can simply melt the butter to about 180 F, toss in the eggs with the hot tarragon/vinegar mixture into a stick blender and then pour in the butter. Run the stick blender at a fairly low speed. Et voila-- béarnaise sauce! I like the idea of saving leftovers in a vacuum seal bag. I typically spoon my leftover onto a cling wrap sheet and then roll it into a sausage. Refrigerate and you have herb butter to slice off when cooking a steak!