How about you just bring an extra cassette or two with some taller gears for the climbing, and just make the swap the night before after talking to a few people? I would think a 28 would be tall enough for any climbing with a 53-39 standard setup. Knowing most of the big climbs in FL, where many are 15% and a hammer fest for 1minutes, and not long 5% grades in duration, you have to be able to turn a wattage/rpm for a specific distance/time. Hence, to maintain pace with any good climbing and a specific speed, having a taller cassette is really not useful.

So I guess the point being, if you know the climb grades for the stages, you should be able to guess the tallest gear you can turn and maintain the threshold. Otherwise, you need a higher wattage threshold, and shorter gearing. Either you have the wattage output at a specific gearing, or you don't to keep up with the top guys.

Since you are built as a climber, lower weight/height, and you know your threshold, you should know from experience, even in Florida, what gear and speed you can turn during training to maintain pace with better riders/climbers.