A couple of issues to think about:
1) people sometimes say their animals weren't brumated when in fact they simply mean they weren't put thru dramatically lowered temps, with no food or light, for a long time: I often talk to people who acknowledge well, yeah, the house was cooler for a couple months over the winter, and yeah, there were windows in the room so the quantity and duration of light was less/shorter for a couple months, and, yeah, the snakes did seem to eat less over the winter. If you consider brumation to be a process of DEGREES (and i'm not talking temperature specifically here!) then i think a lot of animals are modestly brumated even without the keeper's intent: They experience environmental change and it's possible that change, however slight, is enough to stimulate the biological changes necessary for reproduction. So at least keep that in mind when evaluating your animals and the reports you hear from others about their experiences.
2) perhaps it's possible for animals to reproduce with no brumation at all, not even small degrees but i think your odds of success will be heightened by brumating.
3) With 2) in mind, why limit your options to brumating for only 2-3 weeks? you could stop feeding now, reduce temps 2-3 weeks from now, brumate for 5 weeks, and be bringing the animals up at the first of april. Lots of people routinely cool their colubrids til march anyway. there seems to be a trend right now of people cooling only until the first of feb in order to have babies hatched for the big august daytona show. But the brumation period can be shifted to early or late, i think, if managed properly. There's a lot of elasticity there.
peace and good luck!
terry dunham
albino tricolors
st pete, florida