John,
The secondary node was rather large so a post TX "Selective" ND to remove the remaining "still rather large" mass, tends to make sense to me.

Keep in mind that a PET/CT is a diagnostic tool that has limitations and at 8 weeks could show a false positive or false negative.

Most important is to have a surgeon (or team) well experience in ND surgery.

My ENT assisted when I had mine, but the lead surgeon was an elderly prof who arrive late with a few med students in tow.

It wasn't painful - but left a wicked incision that is now nearly invisible.

I would think, and hope, in your case that unless something unexpected shows up on the PET they will just go for the large node and not open you up for an exploratory. If so, in the hand of a skilled surgeon it should go well - but, ASK!