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My recipe is 3g of syrian rue and 5g of mimosa rootbark.
I boil each separately for 30 minutes and pour off the liquid. I add a little vinegar to the pots, but no lemon juice. This tastes much better. The vinegar may not even be necessary.
I drink the rue first and wait for it to take effect (20-30 minutes), and drink about half the mimosa. If the result isn't strong enough, I drink some more. The full 5g is quite strong for me, but I always have it there if it seems right to go further.
There is probably no advantage to separate boiling, nor to waiting between the rue and the mimosa, as most recipes just put everything in the same pot. It's probably merely a superstition.