In a wet/dry set up no laterals enter the wet line, only side mains enter and at that point they are designed to split the wet from the air and gases. Thus you should keep the mains or maybe even shorten them but keep them, as each main comes off the wet/dry have a valve to isolate that main and then run all of the 3/16 into it. I have done this in about 2/3 of my bush and will do some more before next season. With the vacuum on the main, you can use 3/16 even on flat ground, I did it as an experiment on 3 laterals this year where many of the taps were at or some even lower than the main, when the vacuum was one at 26-27" I could not see any difference between those flat 3/16 laterals and the ones with just medium slope and total drop.
I have 3/16 on lines ranging from about 14 all the way up to one at 41 taps. I will split the 41 for next year into 2 lines, then my max. will be 30-33 taps on a 3/16 line. They just seem to work well and the part I like best is that the sap never gets passed by the air (gases). That alone helps keep the lines cleaner.
While my sugar was at record low this year, had it been at my 3 year average from the previous 3 seasons I'd have gotten just over .4 gal/tap in syrup.
Dave Klish, I recently ordered a 2x6 wood fired evaporator from A&A Sheet Metal which I will be converting to oil fired
Now have solar, 2x6 finish pan, 5 bank 7x7 filter press, large water jacketed bottler, and tankless water heater.
Recently bought another Gingerich RO, this one was a 125, but a second membrane was added thus is a 250, like I had.
After running a 2x3, a 2x6, 3x8 tapping from 79 taps up to 1320 all woodfired, now I'm going to a 2x6 oil fired and a 200-425 taps.