Retirement tax questions

I'm also confused because I have to choose to either convert shares, and not know how much the conversion amount will be exactly, or sell stock, let it settle over 2 days, then re-buy the same stock, and not know how that will affect my shares.  I'm tending to go with shares conversion so I don't hop in and out of the market, and hope I don't go over the 12% tax bracket. Any advice?