SH, from what I understand, d-amp only has a 1:1, DA:NE, release, and when you consider the subjective potency of DA to NE, a normally used ADD dosage of Dexedrine has very little NE release that we can feel. I have inattentive ADD, and nod quite often on Dexedrine, I need to use caffeine or ephedrine or another PNS stimulant in low dosages to counteract that.
That "kick" from the Adderall has all sorts of side effects, though. L-amp is so powerful and nasty that it actually changes your personality when you're on it, you might not notice it but your friends and family certainly do. It induces much more of the autonomous, robot WORK!WORK!WORK! ethic, which can be tiring and annoying when you're not working. It also flattens your emotions and blunts your creativity, I have no idea how L-amp is so powerful compared to Ephedrine, chemically, maybe better BBB crossing and more CNS NE release? And these are at low dosages, I've never taken more than 7.5-10mg of Adderall IR at a time, I take no more than 5-7.5mg of Dex IR at a time.
What I do, like you mentioned, is actually make my own combos. I mix Dexedrine to Adderall at a 2:1 or 3:1 ratio, which is basically what you mention, during the rare times I can actually get my hands on Addies. I usually take Dexedrine to Caffeine at a 1:5-1:7 ratio, or Dex:Ephedrine at a 1:1 ratio. I agree that the Adderall has too much kick, and think that replacing L-amp with Ephedrine at a 1:10 replacement ratio would actually be a better choice for a new Adderall formulation, as L-amp is so potent and nasty. The only problem is that it would look so stupid to pick up your generic "Dextroamphetamine sulfate, Ephedrine HCL" at the pharmacy. Soccer moms would gather in legions to decry putting "asthma medications!!! omg!!!" in to little Johnny's Adderall. 8)