It's not possible to use the logos4 protocol to open a layout. I made a small AutoHotkey script to acomplish just this.
How it works
By renaming the Logos.exe file in %UserProfile%\AppData\Local\Logos\Logos.exe to Logos8.exe I can now compile a small ahk executable and name it logos.exe and put it in the same directory.
This small file handles the logos4 protocol and if it finds my new "layout" command it opens the Layout else it forwards to logos8.exe where it was originally intended to go.
In Logos I can now use my custom link, logos4:layout|Bible and Commentary
This script can only handle spaces and the pipe char as I don't need any extra functionality. I just thought to share this trick as I saw a lot of users strugling with this restriction.
The possibilities of what you can do next with this sample is actually awesome. But, I leave this creative expidition to you ...
Source Code (AutoHotKey)
#SingleInstance Force
#Persistent
#NoEnv
HayStack = %1%
Needle := "layout"
If InStr(HayStack, Needle)
{
arr := StrSplit(HayStack,"%7C")
inputstr := arr[2]
StringReplace, output,inputstr,`%20,%A_Space%,All
comobj := ComObjActive("LogosBibleSoftware.Application")
comobj.LoadLayout(output)
}
Else
run, %A_ScriptDir%\Logos8.exe ,"%1%"
ExitApp