I too am a heavy ADHD dude. If you are much past college age the speed starts getting wierd - try Straterra, it's been terrific for me.
As for pot usage: Practice makes Perfect. My wife has similar tolerance issues - so you are a cheap date: take a toke and wait 20 minutes: remed if needed.
Most important is your med selection. Only Sativas or light Hybrids during the day to add focus and cheer: Apollo, Blue Dream are great sativas that really increase your focus and happy zone. Also try Flo - it's a 60/40 that is uplifting & relaxing and a great antidepressant. Blueberry is a very happy influence, but sleepy, so look for hybrids with sativas to keep you alert & happy. Save the Indicas for TV time and especially as sleep tonics (White Rhino) as with your ADHD you probably sleep like shit which increases depression.
Generally most depression I get is ultimately caused by frustrations caused by the ADHD.
Research strains like mad - become your own ADHD doctor and take control of your life. You will always be different from others but you can be happy too!