I wet sanded the filler along the perimeter of the cabin top door opening. It will obviously need more work but the fill looks very nice. I test fit the McMaster-Carr door seal and it does require some additional work to fit well. I did what so many other builders recommended and filled the door seal cavity with a mix of flox and Cabo and installed along the full perimeter minus the bottom edge of the door opening. I did not apply this concoction along the lower opening edge which is the correct thickness to accomdate the seal.