Seems like a lot of unnecessary expense and effort for something that is so easy to do with what you have. All you really need is an inexpensive source of low pressure air. Personally, I feel a lot safer with filling all the pipes with pink stuff, and draining the water heater. I do like to open all drains ahead of time and drain as much as will, su that I do not have to flush water into the holding tanks. Usully I have enough overflow of pink to take care of the holding tanks. One word of caution, with either or ANY system, do not forget the drain traps!! Draining or blowing will NOT get the water out there. Use enough pink down the drains to make sure!!!