That fight is now3 months away, how easy is it to 'fix' the cardio issue in such a short time, and will a fix only give him another 2 rounds??
This isn't really answering your question but its connected to the cardio side of things and I think JK spoke about this recently for preparation for the next fight.
For 189 & 194 McG spent a good part of his training camp in LA before going to Vegas in the last few(2?) weeks. For 196 McG stayed in Dublin for most of the camp, travelled to LA about 3 weeks before and then only moved onto LV about 5/6 days before the fight. I've never been in LA but I'd imagine its a lot easier to breath with the air coming off the Pacific than it is to get a breath in the desert heat of LV. I('m not fit but) noticed feeling short of air when I was in Vegas and I wasn't in the middle of a fight! So I think going to LV a bit earlier, giving more time to adjust to the heat/humidity will help in terms of not gassing just as quickly during a fight.