Hans-Erik,
heaving to is not necessarily about extreme weather. The manoeuvre is just meant to be an easy method to let one take a break. When I had my 23’ Albin Viggen, Malena, still with a Bermuda rig, it was standard practice to heave to when the mainsail was to be reefed or unreefed. I have also read about travellers who hove to while waiting for the sunrise before approaching a harbour or tricky inlet of some sort.
To give an idea of the size of the drogue, mine, at 0.18sqm is 1.2% of the sail’s 3-panel top section and 1.8% of the two last panels. On your Jasmine, I guess a 0.3 og 0.4sqm drogue would do fine. I have made drogues of that size, and they are not difficult to manhandle. Making the drogue too big will probably kill too much of the speed so the boat will not head up enough. ( I need to test my setup with the drogue tied to the weather quarter...)
Ending the heaving-to is easy. Just let the sheet go and then raise as much sail as you want. Then haul in the drogue with the sheet still slack, and finally resume sailing. This is easy. I do it every time I go sailing alone.
Just as with heaving to with a Bermuda- or gaff-rig, one must practice a little with the method on a breezy day. Long-keeled boats are known to heave to nicely, but many fin-keeled boats also do it just fine. My armchair hunch is that even fin-keeled boats, which heave to badly with a Bermuda rig, will behave better with a JR plus drogue (or even Bermuda jib plus drogue).
The obvious drawback with the drogue method is that one must have a drogue. A bucket in tow may work, but that is only 1/3 the size of my present drogue. However, stitching up a parachute drogue can be done in an afternoon. I use offcuts of sailcloth, left over from making my sails. It could even be a fine start-up project for wannabe JR sailmakers to get a bit sewing machine practice.
Cheers,
Arne