Thank you for giving me the opportunity to assist you. I will give the best answer that I can with the information provided.
1. For withholding options, you don't get to use a %, you have to use single or married status, and a number of exemptions. Generally, Single, 0 generates the most withholding, and if this is still not enough, you can opt to take more tax out with each paycheck. Without knowing your income and deductions and entire tax situation, I would not be able to tell you exactly what withholding to use--but single 0 is the highest withholding rate.
2. If you are covered by an employer sponsored retirement plan (the box for this on your W2 would be checked, your IRA deduction may be limited or not allowed at all. For example, if you are covered by an employer plan and your adjusted gross income is more than 66K, you are not allowed to take an IRA deduction. Your other options would be to contribute to a Roth (which has higher income limits) or make non-deductible contributions to a traditional IRA.
3. If you itemize deductions, your medical expenses must be greater than 7.5% of your gross income to make an impact. If you don't itemize, they would need to be a lot higher.
Please let me know if you need additional information.