Having a more detailed look at the current plan shows that LGW/MAN-SFB flights will be a MYT A330 from 29Feb. It becomes a TCX callsign from 30Mar but I dare say it's the same aircraft. The above is to cover planned maint on the XL 763 fleet. From 1May LGW-SFB reverts to XL 763 and MAN-SFB will be XL France A330.
Interesting to read about the AAI 744. I understand Florida bookings are really strong at the moment due to the weak dollar so I wouldn't be surprised to see extra capacity being sought. We'll see in time no doubt.
Cheers