How much of a "premium" would you request for non benefited position?

I'm thinking about 10% for no PTO, no health insurance, or education pay and I will pay my own malpractice (about $400.00 per month in Florida). They will still pay the employer portion of social security, Medicare, and Medicaid, and work comp required by the state so I would not be 1099. I have worked about 15 years without health insurance (as an ICU nurse) and cannot afford it now with my massive student loan debt (I'm 50 and hope to make it to 65 to become Medicare eligible). Thus, the starting pay for new grad PMHNP is around 110K in central Florida. I'm thinking of asking around $54.00 per hour with the $4.00 basically covering my malpractice insurance. I expect to bill them for 32 hours per week,but will spend closer to 45 to 50 with charting and ancillary tasks ( If they want a commitment I will offer one year with no more than a 5K penalty for early breech.)