Just to add, the "Orbital Elements" field is something very particular, only needed if you are trying to catch a NEO object 🙂
Personally I prefer using RA and DEC, together with a fixed time plan. The reason is that using the astrometric option would center on the comet head - this work when the comet has only a small tail, but when you are coping with longer tails like with C/2022 E3 right now, you would end up wasting part of the field of view 🙂
