Multi-Manual Synthesising Suggestion

[Niet]

The crafting window will have the item you just made selected when you finish crafting it. Assuming you still have the mats in the quantity/quality you selected the last time, you can start another one by hitting Confirm (default keybind is numpad 0) twice.

And of course, you can re-bind this. I actually have G added as an alternative keybind for Numpad 0, which is handy for when I'm playing the game one-handed.