I am going to have to say the Sherrifmuir. I am keeping in mind Phil's wise words here about the heat. Also as I understand it is not obligitory that one wear jacobite lace and cuffs with the Sherrifmuir which give some options. I might have gone for the Regulation doublet, but I can't say I am a fan of bowties.

Also I would like to bring quick attention to this doublet (or at least that is what the site calls it) http://www.highlandclans.co.uk/Appin_Kilt_Doublet.html