Just go for broke and let the colony get big. When i did that, i actually made a nice little chunk of change off them. I mean not enough to retire and buy me an island but they paid for themselves and allowed me to basically buy stuff like hornworms and butterworms for free more or less.
And assuming they are warm enough to grow, they will breed. Maybe not at light speed like if you keep them around 85F but they will breed lol. Also give them some orange slices and watch the males go bananas after they eat it haha. It's like they go into overdrive and chance the females all over. Pretty funny.
And yeah, the alfalfa is their staple as it is good for beardies and gives roughage too.