Ok, this is from a Russian language mgazine, having a feature of the su-33. They said successful take-offs have been made from the Kuznetsov with the following conditions:
-With full fuel load, and 4 missiles (weight almost 30000 kg), take offs have been made form the 1st starting position (to the left is the 2nd starting position, then the 3rd position, which is intended for the su-25utg, with the longest run up distance), with a forward speed of the Kuznetsov of 7kts.
-With maximum fuel load, and full missile complement (8xR-27E, 4xR-73, total weight: 32200 kg) take-off should be from the 3rd starting position (take-off distance: 195m), the Kuz should travel at 15kts.
So everything up to 30000kg is alright when using the vanilla take-off position in lomac (Don't know if you can change it with those .lua scripts).
The maximum normal landing weight (not specified wether it's for a carrier trap or runway landing) is 24400 kg. The maximal allowable landing weight is 26000 kg.