I am looking for clear coat for RC airplanes that can resist the  methanol, castor oil, and nitromethane that our fuel is made from along with the heat and combustion by products of the exhaust. From what I see this will work great in that application and the fact that it's brushable is a huge plus. Household latex is a popular color coat because it's light, inexpensive, and has limitless choices in color but needs a top coat. Can the Diamond finish be applied over fully cured latex paint without the solvents attacking it?

Yes, as long as the latex paint is fully cured, the DiamondFinish Clear should go right over it.  This is a very common application.  As always, please do a small test area first before proceeding to a larger area.

You can find complete directions for DiamondFinish Clear Coat here: http://www.kbs-coatings.com/diamondfinish-clearcoat-info.html