Hi there freelance rates for challenger crews are pretty much the same wether 601/604 or the 300.You should be charging £600a day Capt £400 f/o plus expenses.Full time rate £85k capt £60 f/o.There is a large demand for challenger crews at present so don,t undersell yourself.As for operating 24/7 then i would not recomend it!!push for a third pilot (Capt)
otherwise you will have no life,especially if you are married or have a partner, they will need to know when you are off/on duty.
Make sure you have a company phone plus company credit cards,don,t accept the use your own credit card & i will give you a float, it never works in your favour especially with expense rate fluctuation.Otherwise there will be a high crew turnover.As for the no insurance well try going sick or breaking a limb in some places like the usa & kiss your years salary goodbye in one hit.You must have insurance for the area you will be operating.Last worldwide i got inc USA was about £500 a month from bupa very expensive. Good luck