From Wazeopedia

How to create a best-practice permalink

The basics

Creating a permalink has a few hidden pitfalls that may not be immediately obvious to newer users.

Limit your selected objects to 20 max.

First of all, permalinks, while can select a near unlimited number of segments, should be limited to 20 segments/objects. Trying to load a permalink with too many selected objects can cause a load failure, which won't select anything.

Ensure all elements are on the screen

When using the permalink button, the editor also notes your lat/long coordinates so it knows what part of the map to load into memory. If your selected elements are off-screen when creating your permalink, they will likely not be selected when someone uses your permalink. To ensure that varying screen sizes are taken into account, if you're on a screen using 1920x1080 resolution or higher, make sure all the elements are centred on screen too.

Zoom level matters!

The zoom level is important when creating permalinks, because if you're too far zoomed out, some elements don't get loaded by default, even if they're selected in your permalink. Use the below table as a guide when creating permalinks so that the appropriate elements get loaded when the permalink is used.

Zoom level Elements not loaded at this level
10 (Lowest) to 5 None
4 Some Point Places
3 Street (Road Type)
2 Private Road, PLR, Narrow Street
1 - 0 (Highest) Everything except some large map comments & large Area Places (not recommended)

Use the below table to determine what zoom level you're on. (Use the scale reference on the bottom right corner of the editor)

Zoom Level Scale (Metric) Scale (Imperial)
10 2m 10ft
9 5m 10ft
8 10m 20ft
7 10m 50ft
6 20m 100ft
5 100m 200ft
4 100m 500ft
3 200m 1000ft
2 500m 2000ft
1 1000m 5000ft
0 2km 1 mi

Always test your permalinks by using them yourself.