What would a contract worker charge to move from part-time to full-time work?

I am “self-employed” and do hourly contract work for this one company. They are looking to give me “full-time” status, although I would still be under contract and NOT a salaried employee. I believe they are looking to give me a yearly rate (to be paid monthly) instead of hourly. So my question would be, how do I figure out what is an appropriate amount to charge? Do I (a) just keep my hourly rate and multiply it by the average of 2,080 hours in a year; (b) ask for more than that because they would have higher expectations of my work now that I’m full-time (and I could potentially be working more than a 40/hr workweek); or (c ) ask for less because they are guaranteeing that I make a certain amount and I have more security (even though this is false security since I’m not salary)? If anyone has insight or lessons from experience, I would greatly appreciate the feedback. Thanks!