Hi Tom,
perhaps this method will give you the rounded peak needed.
I started with a square and added mid points to each side.
Then selected the mid points and scaled to give the desired curvature,
Offset copies made and added point for peak then lofted as per Burr's video.
Added a fillet running diagonal from corner to corner.
The other diagonal same radii but requires a second fillet set for the peak area to be slightly smaller.
hope that makes sense.
Cheers
Barry