Thanks for referencing my article, Maurice!
What I stated there certainly can be tweaked. As RedAlert mentions, a 3.0 ohm atty should be fine: 8.3 watts (very nice) and 1.7 amps (not too bad).
I think that 2.3 ohms (i.e., a standard 510 atty) on 5V is a bit much: 10.9 watts (too intense for me) and 2.2 amps (won't blow up or anything, but will shorten atty life). But ... whatever works.