Hi, I can actually help with this. I think you would want to make the quarterly estimated tax payments in the name of the single member, and choose form 1040. On EFTPS it will give you an error the first time you try to make a payment, telling you you aren't set up for the form. Just ignore the error and make the payment. It did the same thing to me and I called in and asked about the error and was told to ignore it.