Paat
I'm sure I'm not telling you anything you don't already know, but a crucial factor in these considerations, is your age. I'm guessing you must be early to mid forties?
If you don't mind the time away from home (and perhaps after twenty years in the RAF you don't) then I think, having done both more than once, LH probably offers the better quality of life. This also enables you to live pretty well anywhere in the world that takes your fancy. However you will probably find yourself sitting in the RHS for a lengthy period, if you chose to join any of the majors.
If a command is important to you, I imagine you need to be looking at a SH operator. That could be schedule or charter (personal preference/ geographical location). If I were in your position, I would have little interest in what the various companies pay. The most important single factor is their 'Scheduling Agreement'.
This is how you will live your life, and how the company respect you. There are mature companies out there with good agreements, and there are some well known companies with virtually non existent systems.
Make the right choice first rather than at the second or third attempt. Forgive me for saying, but time is not on your side
You will be entering a totally different world. Enjoy.