Yeah there is the issue of ability to breed.
You could feed twice a week but I would suggest 10% per feeding if you go that route, or just once a week with 20% (if you really need to boost the snakes up in size). After your snake hits 1000g you're looking at giving them 200g/week which means extremely rapid growth, after which you can then reduce the amount they eat and give them some breathing room.
The issue isnt about getting them to size, though, as that probably wont be all that difficult by March, it's about whether or not they will/can breed at that point.