I would always use a garage of shade where possible, as heat from the finish could dry any polish quicker than normal. That said, XMT and SSR's would be my choice for sunny afternoons.
I've used all of the XMT line up in direct sun in 95+ temps. Does super and give use plenty of work time. So far, looks good on any color. Just top the glaze with Max Wax or Souveran for best results.