Brien,
Last year I added AUF to my barrel evaporator and went from 7L/hr to 14.5L/hr. Since I don't have electricity either I have a battery and a 12V fan to add the air. It was a major upgrade for me. I was hesitant about RO since I was only 32 taps and the cleanup and hauling sap out of the woods to do the RO and bring the concentrate back.
2021 - Year one. 15 taps using 5/16" and drop tube into buckets. Homemade barrel evaporator with 2 steam trays. 4.7L syrup.
2022. 32 taps. Added AUF.
2023. 51 taps. Ditched the steam pans for an 18x22 flat pan.
2024. 56 taps. Built a proper evaporator to fit the 18x22 flat pan and 1 steam pan.