Plugin version: v10.3.5
Game version: v1.10.0

Config settings

  sneak-to-place-field: <true|false>
  sneak-to-place-normal-block: <true|false>

seem to always take priority over a field's sneaking-to-place: <true|false> setting making it not possible to have some stones sneak-to-place and some standing to place. Setting the plugin settings in a way that conflict with the field's flag setting makes it impossible to place the field at all. Example:

- title: '&cTest [v7]'
  required-permission: preciousstones.test
  sneak-to-place: false

...
  sneak-to-place-field: true
  sneak-to-place-normal-block: true

It is entirely possible that I am doing something wrong, but I've tried several combinations of these settings and this is the result. The goal is to make some stones only place-able while sneaking and some only place-able while standing.

To be honest I think it'd just be simpler to remove sneak-to-place-field and sneak-to-place-normal-block config options and leave that to a per-field setting with the sneaking-to-place flag. Having 3 options to control the same thing leaves too much chance for conflict.