Hey there Fly-A-Kite!!
If you haven't used STs before, I really recommend you going onto that
www.sunless.com site that I mentioned...it's relaly helpful to do some reading!! (About how to apply, etc.)
My skin tone is a light-to-medium yellow skintone (I'm Asian american if it helps any). I think it would look great with your medium skintone!! I use "Dark" which is fine for me, or if you want a more natural one, use the "Light to medium" color. (Though Dark is relaly natural.)
Oh yes, 30 minutes is sooo much better than being burned out in the hot, hot (not to mention damaging!) sun!!!!
Keep us posted!! P.S.Coppertone's Endless Summer is great b/c it combines lotion w/the ST...so it makes for smoother (i.e., streakless!) application!! Just make sure not to apply too much to one area (be consistent)....ALSO, be careful around the hairline, and Really BLEND, BLEND, BLEND!! And also, use a Q-tip around your nostrils, ears, and around the eye brows to kinda "feather" out the ST...so it blends (sometimes the ST can gather around those areas). ALSO, put a coat of Vaseline (petroleum jelly) on your eyebrows and on your lips--othewsie the ST will tan that, which is totally unnatural!
(BTW, I learned these tips from Allure mag.)