dmertz-Thank you so much for this further clarification. I see what you are saying and now understand how to do it. I have looked at Schedule A1. It seems time consuming and tedious but not complex. I have/will have the needed data and can definitely do it if needed. Just hate having to spend that much time, probably two full days to do it.
In any case, it is very helpful to know all the options available for getting the right amount into the fed's coffers at the right time and in the right manner (withholding vs est tax) so I can pick the best one for this year's situation.
