I used to be prescribed Adderall XR, 25 mg, b.i.d. What I would do was, in the morning at around 8 or 9, take one capsule, pour half into my mouth and chew up the beads, holding and swishing it all in my mouth for as long as I could for whatever sublingual/buccal absorption I could get out of it that way. Then I would repeat the same at about 11. At around 3 pm I would take the 2nd capsule and do the same thing, but would swallow it as soon as the beads were chewed up. This would get me pretty much through the day, and by around 10 or 11 at night I would be set for bed. Most afternoons after the last dose, I would get a fair amount of exercise, skateboarding for usually 2 or 3 hours after class which helped keep me in good shape, combined with forcing myself to eat regularly, and sleeping (being active every day helped this). After an old Ambien prescription of mine ran out, my doctor gave me 100 mg of Seroquel for sleeping, of which I would only need about 25 mg on most nights.
But yeah, that's pretty much how I was able to get the most out of 50 mg a day. You could try the same thing with whatever amount, keeping the ratio of 1/4, 1/4 then 1/2 the same.