I am looking to fly DFW to BCN and connect through LHR. I have 125k Avios and want to book with cash bc I need the EQP's for a challenge. I’ve read the best redemption is to book WT+ and upgrade to Business. My dates are flying out July 3rd and fly back July 14th.

I need suggestions on how to keep track of this and find upgrade availability because BA has no waiting list I would like to wait to book my ticket when I know for sure I can upgrade. When I do book with cash and upgrade with Avios search on BA.com not only do I find nothing for my dates but I don’t find anything, (literally nothing) for every single day from now to July? I’m confused on how so many people accomplish this upgrade?

Any help would be appreciated.