Hi
I have a paper GPU in hand for the second leg of a trip next week (LH442) from FRA-DTW in Q on 11/26. (First segment is LHR-FRA)

I've never used an LH GPU before and am wondering how to maximize my chances of it clearing. LH's seating chart for the FRA-DTW flight shows about 1/2 the J cabin is wide open but I've read elsewhere on FT that LH will sometimes deny GPUs at the gate if the flight hasn't loaded enough J meals onto the plane even if there are 20 empty seats.

Is this true? And if so, is there a way to enter the GPU into system/waitlist myself when I initially check-in at LHR earlier that morning? Or do I just present it at the gate when connecting in FRA and hope for the best?

I couldn't care less about the meal. I just want the seat! Judging from the # of J seats that appear to still be available it should clear but I'm being paranoid because I've never used these paper things before.

any tips would be great
thanks