I believe both of them are not full fledge glaze but abrasive cleaners rather, both cut on the paint, the oils they may contain may be for lubrication only.
In my case I always break down my process to polishing and glazing as two steps. Glazing is an optional step if you want to add some more pop on the finish which you have cut.
Yes you may want that SCG or #81, or even #80 speed glaze as an additional step. #80 enriches the paint color more than SCG and #81 at least for me, but that is subjective. It's up to you.