BPA strongly favour notching, and if you double tag, then you must get their permission first, and if they lose a tag, then it gets complicated.
Once you have chosen a system, then I think you're stuck with it, so you may want to query now, rather than notch this lot and then want to tag the next or visa versa.
Tags on a small pig can look very silly !
Your choice obviosuly, and if you're selling weaners as pedigree then buyers may want notched pigs if they plan to show - or they may be happy with double tags - and non pedigree buyers may be unhappy with notched pigs - you pays your money...