I'll answer the OP.
5.0.
Since it appears that the JB software will support it, I'll stay on 5.0, JB, then upgrade to 5.0.1 while preserving the baseband. That way, I could still beat the signing window for 5.0.1 and keep the potential ability to unlock.
BL.
That is my exact goal too buddy, let's hope this all goes smoothly