SIP can be a very funny polish, when it works, there are only a few products that rival it's performance, but when it doesn't work it can be the ultimate excessive in frustration!
I am not sure which machine you are going to use SIP with, a DA or a rotary?
One of the good/bad things about SIP is that is has a very long lasting, very thick lubricant. This stuff has work time on top of work time, which can be very beneficial in particular situations. The down side is that the lubricant can be very difficult to remove from the paint completely. This same super long lasting lubricant remains wet in the pad, so as you add more in more fresh product you are really saturating the pad with excess amounts of this lubricant.
If you do not keep your pad very clean, and switch to a fresh pad often it can be difficult to access when the SIP has 'broken down' completely because the thick amount of lube will never appear to turn opaque. Keeping your pad clean, and switching to a fresh pad often, will greatly increase your ability to judge when the polish has broken down completely, as well as prevent the working time from becoming excessive!