Hmm - This will interesting. I'm not all too familiar with the flyxii model of frames:
Does anybody know which if these frames is the equivalent of the 057 and 256 frames?
We'll find you the best frame once we get all the different models sorted. Til then, it looks like you should have plenty of stem left on your fork, which is good.
Two criteria that you'll need to check off your list is you'll need a standard BSA bottom bracket frame, and standard QR rear axle, bc I believe the expert model black flags aren't capable of converting to 142x12.
So, to get you started - your frame must be:
1. standard BSA bottom bracket
2. standard QR rear axle