第一計劃也叫403B?我記得我們這裏的新雇員可以選擇Retirement Savings Plan：

You contribute 8.0% of your eligible earnings. Employer matching
contributions begin with the first full payroll after your plan election
is received. Your contributions and the employer contributions
will be made based on your full salary, up to the IRS 401(a)-17
annual earnings limit. 

你的第一項是必需的，主要是拿到match。自己投資，走index，自然也是定投。。。2和3，4和5當然是有多餘的錢才會考慮。你應該沒有Social Security tax。看年齡和家裏另一半的收入，尤其是退休後的收入來決定投多少到Roth。我自己還會看每年的margin tax rate。我是通過401K/403Bcontribuion的多少來控製每年的margin tax rate的。