[graybass]

Holy moley,
You sound just like a figure competitor that I'm training right now.
To gain that much weight, that quickly, a great % must be water. Not all of it though.
Remember, it's considered ideal to lose about 1lb per week.
also I hope your not doing 2-2 1/2 hrs of cardio in one session. If you are, you'll be losing just as much muscle, as fat.
Bottom line, Everyone is different, maybe you can do it, if every thing is perfect.
I've been training cliets for almost twenty years, and usually the longer road is better. Most precontest training is at least 12 weeks long.(as you know)

PS, where are you competing ? My girl's going in a national qualifier in Jersey.
And, that amount of cardio would work best in two sessions, one morning, one early evening. (with rest and food in between)

Good luck graybass