I will echo MSP’s caution about the strong possibility of schedule and aircraft changes between now and then. Normally I say to go for whatever you can afford (we all deserve a nice treat!) but I have run into issues where I have booked C+ and been rebooked on planes where C+ no longer exists and thus downgraded to Y. I have also had the opposite where I was in PS and thus downgraded to C+. It can be tricky and a headache to get downgrade compensation plus a refund after travel is flown.

I guess if it was me I would go with whatever option would keep me on DL metal for now and avoid a partner with all of the possible changes looming for simplicity reasons.