404 Titan
I saw both your replies, edited & unedited. I must admit it makes my head ache a bit with the effort and possible traps involved.
I'm not having a go here (you may well be a senior pilot), but is launching and replanning enroute on the basis of weather at aerodromes that are never really considered as alternates advocated by the senior guys where you are. Leaving aside off track PNR situations.