My missing double TPs have arrived and I am finally GGL at long last!

Just to double-check, since my membership year (currently) ends on 8 May, am I best off doing one set of nominations before then, and another afterwards? Or can I only do another set of nominations in my next membership year after earning 3000 TPs?

Does the same go for Joker redemptions - I've heard suggestions that you should book 'throwaway' redemptions (if you don't have any firm plans) to preserve your Jokers before they are reset at the end of your membership year? And can anyone confirm whether they've been able to use a Joker to unlock availability for a Barclays Upgrade Voucher? I know the terms of the latter say it can't be used in combination with anything else, but these kinds of rules often don't seem to take Jokers/GUFs into account. I understand that you definitely can't use a GUF1/2 with a BUV.

Thanks in advance, and look forward to meeting some of you in the CCR soon.