hey up mate
just progress nice and steady , if you are happy with how things are going at the moment then keep it that way . if the mans wages are being paid and you are making extra on top of his workload then you are in a winning situation , if you are only breaking even then give it a while longer and see if you start to make a profit , if you aint making a profit its then time to consider you options .
1 stay as a sole trader
2 keep paying wages for little or no profit
3 build up your work so the guy is making you a decent profit .
dave