If it's a positioner that you're clearly making for a subsequent live commercial sector it's N, especially as your customer has almost certainly paid for it as part of the price. Ditto the sector at the end to base.
I doubt you will find hard and fast rules, but the Authority will take a dim view of you positioning in as a G to evade commercial rules (like a Cat C airfield) or as a last sector to fudge FTL.