Two different characters on two different accounts, each one capped at same level.
Each character would start crafting at same time, on the same recipe. Why? This is mostly obvious.
It eliminates situational factors, like:
Day of the Week
Direction (both faced same direction for every synth)
Moon Phase (both started a new level at same time)
It has been speculated that different recipes have different skillup rates. I don't know if it has any merit or not, but by using the same recipe, it eliminates this possibility. Furthermore, I am using the same recipes as I used in the Shaper's Shawl thread, for consistencies sake.
Staying withing 5 levels of known recipe cap in order to give both characters a chance to skill up off breaks.
(I don't believe in the direction stuff, but doing two characters at same time makes it easy to make the only variable the cape)
No NPC synth support on either character at any time.
Each character stopped once a level was complete to wait for other character to catch up.