ATK recommends settling on one pot, which can perhaps accommodate various needed sizes, that way you have a consistent amount of evaporation.
If you use different pots, with lids of perhaps different levels of sealing, then your results will be all over the place. If you always use the same 2-3 qt/L pot, you'll always get the same evaporation.
If you use different pots, with lids of perhaps different levels of sealing, then your results will be all over the place. If you always use the same 2-3 qt/L pot, you'll always get the same evaporation.