Hi DC10 won’t comment on is it worth it question as others have helpfully given a view. My experience was last October had same issues as you with on line request and email to PC - useless.
So braved the airport upgrade process, you need to get there sharpish just befor when check in opens - 3 hours before . Go to customer service desk at end of check in row and ask there . They will check with supervisor and if agreed will fill a form in for you to sign . You can then go to FC check in counter to complete the process. On the day I did it there were 3 others that also requested an UG . Process was very easy and quick - unlike on line and e mail .
I checked expert flyer a few days before flight to keep a watchful eye on F availability . Good luck and please post back

cheers