I did some testing; this is what happens when I try to start your permission with my server:
[31m[10:14:44] [EXCEPTION] Error while loading permission 'delta'
[31mInvalidCastException: Unable to cast object of type 'Int32' to type 'Single'.
at RisingWorld.Common.Permissions.Permission+PermissionKey`1[T].Set (System.Object value) [0x00000] in <00000000000000000000000000000000>:0
at RisingWorld.Common.Permissions.Permission.Parse (System.String json) [0x00000] in <00000000000000000000000000000000>:0
at RisingWorld.Server.Managers.ServerPermissionManager.InitializePermissions (System.String permissionFolder, RisingWorld.Common.Permissions.PermissionType permissionType, RisingWorld.Common.Utility.ArrayList`1[T] storeTo) [0x00000] in <00000000000000000000000000000000>:0
at RisingWorld.Server.Managers.ServerPermissionManager.Initialize () [0x00000] in <00000000000000000000000000000000>:0
at RisingWorld.Server.GameServer.LoadWorld (System.String worldname) [0x00000] in <00000000000000000000000000000000>:0
at RisingWorld.Server.Main.InitServerWorld () [0x00000] in <00000000000000000000000000000000>:0
at RisingWorld.Server.Main.InitServerContext () [0x00000] in <00000000000000000000000000000000>:0
at RisingWorld.Server.Main.OnPostInitialize () [0x00000] in <00000000000000000000000000000000>:0
at RisingWorld.Common.JIWApplication.Update () [0x00000] in <00000000000000000000000000000000>:0
RisingWorld.Server.Managers.ServerPermissionManager:InitializePermissions(String, PermissionType, ArrayList`1)
RisingWorld.Server.Managers.ServerPermissionManager:Initialize()
RisingWorld.Server.GameServer:LoadWorld(String)
RisingWorld.Server.Main:InitServerWorld()
RisingWorld.Server.Main:InitServerContext()
RisingWorld.Server.Main:OnPostInitialize()
RisingWorld.Common.JIWApplication:Update()
I'll try something else again... I'll get back to you... but maybe someone else already knows what this means or where the error lies.