BIN and Isofix are both a shellac based primer so both should do the same job. Apparently Isofix is easier to use but I havent used it so couldn’t verify that.
Oak can sometimes, not always, cause staining through paint so shellac would be the way to go. It’s not easy to apply smoothly though as it dries really fast. It’s best to put it on as quick as you can. Don’t go back over recently painted areas as it will drag and tear the paint. Put it on and sand it smooth. You will only need 1 coat of shellac, don’t give it 2, you only need this for adhesion.
If you have experience of spraying HVLP is by far the best and most efficient way of applying shellac over large areas. Be aware this route isnt for everyone and extensive masking and sheeting will be required.
Little Greene and Tikkurila Empire eggshells are good products but I wouldn’t overlook water based products either. Tikkurila Feelings and particularly Mylands Eggshell with give excellent results and apply fairly easily.
Shellac primers are compatible with both oil and water based top coats but if you intend to use an undercoat prior to the topcoat make sure that system comprises of the same type of products, ie oil u/c then oil topcoat or water based u/c then water based topcoat.