It's impossible to predict whether they will last all weekend, but the correct way to use these tires is to drive them until you see cord. As they get down close to the end, that means you'll need to carefully inspect them between EVERY run-session at the track.

But that is a small price to pay for the awesome handling they deliver in such well-worn condition. I went through several several sets of RA1's and drove each set until one tire showed cord.

You could inquire to see if a tire vendor will be on-site at the track that weekend, and if so coordinate with them to have a new set new ready for you so that if you see cord on Sat you'll be able to get new tires fitted and not miss out on Sunday.

Enjoy your weekend.
Q