There used to be a pot called "The Everything Pot" that came with two inserts, one large insert about the depth of the pot and a second insert that was more shallow for steaming.
I tend to use inserts more for steaming veggies than for cooking pasta.They don't seem to lend themselves well for draining pasta while the pot is on the stove. The minute you start lifting up the insert to drain the pasta, you've got water draining out of the insert holes all over the stove top (which sounds like something you may have experienced).
Have you thought about getting a colander to put in the sink and then pour the contents of your pot into the colander? America's Test Kitchen recommends this colander for such a use.
edited to add here's a video (click) from America's Test Kitchen on their review of colanders and why they chose the RSVP colander.