I am not sure about megs #3 but I am pretty sure that most megs glazes would be incompatible due to their oil content. Most sealants have trouble bonding to oil based glazes and waxes.
I would recommend an acrylic sealant such as Danase Wet Glaze (DWG) or
Chemical Guys and I think there is one from
Sonus as well.
In short, I have seen great results with those combinations!
Good luck and post pics!
-Frank