I believe the three tubing rules are 1 straight, 2 tight, and 3 downhill.
Having said that, down hill only really has to be about 3-4 degrees. (This is off the top of my head without looking it up). As long as your lines follow the three rules, you don’t need a very steep slope. Use side ties to tighten and straighten droopy tubing.
2017 - 20ish taps on buckets, boiling outside in two baking pans
2018 - 70+ taps, 14-buckets, 50+ on tubing, homemade arch from oil tank in my barn, 17 gal syrup
2019 - same set up, 20 gal syrup
2020 - less taps, short season, but RO kit was fantastic! 6 gal syrup and a maple cat!
2021/22/23 - expanded into the neighbors yards! 50 taps on buckets and 40 taps on tubing