Having 2 different size lines, 3 mm and 4 mm probably does not help as it would make it easier if both lines were same diameter. What were both beers carbonated at? What PSI are you set at?

Doing some searching online, the 4mm lines have 2.9 lbs of resistance per ft, 5 mm only 1 lb per ft and what More Beer recommends when long lines are needed), could not find 3 mm...but I would assume maybe 4.8 lb per ft based on the 1.9 lb increase decrease between 4 and 5mm. So part of your problem is the long smaller diameter lines at large lengths seems to be putting a lot of resistance on your lines. The formula for balancing lines is __ Pressure = (Length of Beer Line in Feet x Line Resistance) + (Gravity x .5__). So let's take your Saison., if you put 4 mm lines in instead of 3 then 20 ft 4 mm lines...so Pressure = (20x2.9) + (Gravity x .5), where gravity is the distance between center of your keg and your faucet. So using my 1.5 foot estimate , we then have Pressure = (58) + (1.5x.5) or 58 + 0.75, so you would need PSI of 58.75 to pour that Saison properly. If you cut to 10 feet 4 mm line, PSI would be 29.75, 5 foot 4 mm lines, PSI would need to be 15.25 PSI and so on. Just remember, if you carbonated your Saison or Hefe at say 18 PSI, you want that line calculation to come out to 18 psi, if it's lower than that, over time the keg will drop pressure down to the set PSI and your keg will no longer be carbonated at the volume you wanted.

Sometimes it helps to have different sets of lines depending on what you are serving and what the carbonation level of the beers are, for example, short lines for low carbed English beers, normal lines for most beers, then longer lines for highly carbed beers. However, unless you have more than one regulator to control the PSI of different kegs, you will be serving everything on tap at the same pressure, so would need to plan according. I brew mostly lagers, so for myself, I use 4 feet of 4 mm line and carbonate and serve at 12.5 PSI. Which one more time using the formula Pressure = (4 feet x 2.9 resistance ) + (2 foot height x .5) or P = 11.6+1, so pressure = 12.6. Which is close enough to 12.5 for me. When I do have a higher carbonated beer, I will change lines and only serve that beer until it's gone, since no way I can serve a Hefe and say a Pilsner at the same PSI.