I don't begrudge anyone staring their own business, but it never surprises me to hear how a company just gets out of control. Time and cash flow, rather the lack of these, is often the killer; and real life- job and family, illness etc just add further to ones woes.
One simple way to work out wether you have the time to start a range is to spend an evening laying out a ring of figures onto a nine inch dinner plate.
Put these into ziploc bags, say four to a bag, and then take them out and put them onto the plate again.
Repeat all evening, taking into account any disruptions from your family, housework, phonecalls from freinds/relatives etc.
This reflects the efforts required to pack stock for a show/trade order and does not take into account casting, the trip to the post office, the realisation that your £650.73 in orders goes no way towards the £983.57 that the contract casters latest invoice comes to.
By all means have a go, but remember, your hobby, your personal involvement in the hobby will be the first to suffer.