In the end, I went with a base coat of Sinful Colors Pull Over, a mustardy, golden yellow, because it was close-ish to the base of Quantum Leaf. The pictures above are with three coats of KBShimmer Quantum Leaf over one coat of Pull Over, with a layer of Seche Vite on top. Below is just one coat of Quantum Leaf over Pull Over.
So in the end, I didn't even need a base color, because you can't tell it is there, but from my experience with KBShimmer, the bases have been rather sheer, so I wanted to be on the safe side.
For me, it doesn't seem like we even hardly had a summer. It wasn't scorching hot very often in the Midwest, unfortunately, so it doesn't seem like we should be getting ready for fall yet! It still feels like June to me! Sadly winter is just around the corner. Snow. Icy streets. Freezing temperatures. :( I need to become a snow bird.
Anyway, let's see what all the others Twinsies picked for their transitional polish!
Chelsea at Nailed Blog
ChiChi at I'm Just Me...ChiChi
Cordia at Seriously Swatched
Elizabeth at Did My Nails
Heather at Peace, Love, & Polish
Kelly at Tuxarina
Lakeisha at Refined and Polished
Maribeth at Obsessive Cosmetic Hoarders Unite
Marisa at Polish Obsession
Meredith at Polish and Charms
Nory at Fierce Makeup and Nails
Rachel at Top Coat It
Róisín at Cuti-CLUE-les
Traci at DrinkCitra