STB's got the goods. For weight drop, really, 4 weeks is enough to drop about 8 lbs. If you need 25 lbs TOTAL lost, then if you drop 8-10 in bodyweight and drop the rest in water/waste, you can probably make the class. Have lactated ringer IVs on hand after weigh-ins and somebody who knows how to properly IV you. I know some people like Matt Kroc can drop 20+ lbs of water, but if you don't have to suffer that badly, I wouldn't. I'd rather kill as much weight as possible in advance and then drop the remainder in water.
Regarding cardio overall--since strength is a priority, do a lot of walking as well. Walk everywhere you possibly can. It's low impact, low intensity, and has the lowest possible chance of interfering with your strength training in recovery.
The weight drop is really in the diet--do NOT use DNP. I do not think it's worth it especially if you have any need to train hard. That is not safe stuff to drop into your system.
Regarding diet--man, just write down what you're eating and I will see if I can help. You're on a lot of AAS, and tren in particular is probably keeping your weight up. It's going to be a hard drop in 4 weeks to be honest. IMVHO you should have started the diet 6 weeks ago to make it nice and easy on your system along with the training loads you're gonna have to handle.