With any batt installation layed down on top of blown (any density batt) or other batts you have the issue of the gaps allowing convection to rob performance.
What I WOULDN'T use is cheap low-density fiberglass blowing wools- I'd do rock wool before that, but cellulose is even more air-retardent still. A 3" overblow of cellulose can "restore" low density batt performance to near it's ASTM C 518 test rating, but not low density blowing wools. The test plates used in the ASTM test become air barriers during the test which is why in many ways there's a labeling issue when batts or blowing wools are used in attics without an air barrier on the top side, as is usually the case.) Testing those products in the fixture with an added air gap also doesn't cut it, since the gap isn't anywhere near as deep as an attic space, and isn't vented to the great outdoors. (And attic ventilation rates will vary, making any arbitrary vent rate in a test fixture wrong.) But blown cellulose hits pretty close to it's rating, even without a topside air barrier.
To get best results it's good to set up depth gauges and rake it all dead-even, since a few thin or bald spots can rapidly become the thermal bypass for the rest.
I've occasionally blown insulation as a 1-person DIY, and I can testify that it's a scrambling, tiring. and slow way to do it.