Hi Nomis. Here's what id do( in this order) if I had a stave with bug holes.
1) See if I could lay out bow design around holes so there would be none in the finished product. Even if that means I would need to modify my design.
2) Chase a ring below all damaged wood and use that new growth ring as my back. Even if I have some ring violations I would fell better backing them then I would an insect hole.
3) Look for a different piece of wood.(this here very well could be #1)
The problem with borer holes is not only the spot where they enter but what happens after they decide to "have a look around". There is no telling how much wood 3 rings inside is missing. It would stink if you were on your last few scrapes tillering the belly only to find you discovered where that insect has been feeding for the last 2 months. A pin hole from a powder post beetle can turn into much more. Also water may have entered the hole and there maybe even more wood damaged by fungus or rot.
I understand your question is what would be better. However I think you should look at it as how can I avoid this damage. I'd much rather see a future post from you showing off your 1st self bow( I like pictures
) , than you spend a lot of time and effort on a failed attempt because of some unseen damage.
Regardless on the direction you go from here.... Good luck!
Mike