2 days a week while training is not enough IMO by the time you have got them into any sort of routine they will be off for 5 days and forgotten most of what you have tried to show them they will be terrible slow and slow you down they will not see very many customers so will have no idea on any quirks to the property you want them to clean.
Do a weeks trial to see if you like them and that they like you and the job then do a 2 week 30 training cycle then you'll know early on if they will stick at it and if they work to your standards.
Are you WFP and trad or just trad or just WFP
Darran