To start off, I got tired of forgetting to reset zlevels. So, I decided to come up with a long term solution where I wouldn't have to reset them. It mostly works. 

First thing, I set the level caps at their maximum. I use all the levels and categories, but you don't have to for this to work. 

    "LevelCaps": {
      "A": 200,
      "C": 20,
      "M": 200,
      "S": 200,
      "WC": 200

Next, I set the Points per Hit at the lowest whole value (still waiting on word from the dev whether fractions are viable).

    "PointsPerHit": {
      "A": 1,
      "M": 1,
      "S": 1,
      "WC": 1

That is the important one for slowing things down. At 1 xp per hit, it will take forever to level, even with power tools (which I leave enabled). But, in order for it to make sense long term, I drastically lower the amount gained as bonus materials.

    "ResourcePerLevelMultiplier": {
      "A": 0.1,
      "M": 0.1,
      "S": 0.1,
      "WC": 0.1

This makes it so that, as L2, they get a 1% bonus to their farm. At level 200, this amounts to a 2x bonus. This seems trivially low for the effort, but what I do next makes up for it. 

  "ResourcePerLevelMultiplierAtNight": {
      "A": 1,
      "M": 1,
      "S": 1,
      "WC": 1

What this does is multiply the bonus by 10x at night. What was only 1% per level, is now 10% per level. If they're level 20, during the day they'd get a +19% bonus yield. At night, that's a +190% bonus. At level 200, this equates to nearly a 20x gather bonus. This gets the players out of their base at night. Especially when I do this...

    "PointsPerHitAtNight": {
      "A": 3,
      "M": 3,
      "S": 3,
      "WC": 3

This triples their XP gain at night. Yet another incentive to get outside in the dark and brave the wilds. 
-----------------
Basically, this means that even after a handful of wipes, my players are barely in the 20s in levels. At this rate, I won't have to wipe zlevels for 6-12 months. 

However...

Crafting levels up way too fast for this model. By default, you get 3 per time spent. 

I change crafting XP per time spent to 1. It's still to fast to not be wiped regularly. 

  "CraftingDetails": {
      "PercentFasterPerLevel": 5,
      "TimeSpent": 1,
      "XPPerTimeSpent": 1

Again, I'm waiting to hear that fractions can work and will be tracked at a fractional level. If it is possible. I would set XP to 0.1 or maybe even 0.05. I bring this up because, as is, they'll get to level 20 in crafting rather quickly compared to the rest of my changes. With that in mind, I wipe Crafting for all my players each wipe using zl.lvl ** C 1. 

I hope this helps some of you out there. 

thanks, pinned

Thank you, was trying to set it up correctly since 2 days now... the math behind is not clearly explained.. maybe my english is not good but i don't understand the "per level" multiplier... and now you say that 0.1 per level means that you have 2x a 200 (not 20)... I am setting it up at max lvl 25, with a starting multiplier of 2x and a maximum of 10x at lvl 25. Going back from your math i have to set the "per level multiplier" to 4...  not 0.4. btw the "P.L.M" is not clear for me, clearly it not mean 4x per level.