Larger input hatches definitely do not help. Large input hatches actually hurt the large steam turbines for the reasons I outlined, and a large water input hatch for the boiler doesn’t really change how it behaves at all. About the only thing you get from a larger input hatch on the boiler is a larger water reserve.
My distilled water reserve is a small external tank. Even so, as long as the reserve is large enough to hold all the water generated by the turbines when the steam tank bottoms out, and thus all the stored steam is converted to water, the reserve tank size doesn’t matter.
I’ve taken a couple of steps to address it, because the water destruction was actually getting kind of serious if I put the system under significant load. The destruction is per boiler startup, and if the system runs continuously for a while, the repeated boiler starts (every 12 minutes or so) were outpacing my MV distillery’s ability to keep up.
I’ve added a 2nd MV distillery, which increases the amount of water converted, but the main thing I did was throttle one of the boilers by 5000 L/sec, so they boilers only outpace the turbines by 5,000 L/sec instead of 10,000 L/sec. This means that if the turbines are running continuously, a cycle takes twice as long.