For someone who doesn't have a ton of rune pages so I can't make several different pages for every role, what is generally seen as the best general rune set up for Blues and Yellows for an squishy AP Mid laner?
I have flat armor yellows and scaling MR blues at the moment but was thinking it might be better to have scaling HP yellows and flat AP blues or flat MR blues. Thoughts/suggestions?
It depends on your champion and your lane opponent.
If your range is lower than your opponents (or you have to get in their face to damage them), flat armor seals will help you mitigate minion and lane opponent autoattack damage. If you have the range advantage, you can afford to take scaling health or scaling armor seals. Flat MR glyphs will help you in lane against opponents that do a lot of magic damage early on (ex: LeBlanc); scaling MR glyphs are acceptable against opponents that really need to buy AP before they do much magic damage (ex: Twisted Fate).
With AD lane opponents, scaling MR glyphs are generally a safe bet (just be aware that some AD laners have supplemental magic damage, such as Zed's passive). You'll definitely want flat armor seals unless you're a siege mage (plenty of range and waveclear). If you're playing a siege mage and know how to abuse your safety, you can opt for scaling health or armor seals (I'd suggest armor).
