Waterproofing doors and trunk

I’m surprised there aren’t more questions regarding weather stripping apps.
2 questions;
which do I do 1st; door adjustments for gaps etc, or remove and apply new rubber, then adjust gaps.
I’m getting 2 views from different car shops; Get a complete new kit from Steele Rubber products, apply, then adjust doors.
2nd view; adjust doors, then use replacement parts from someplace like Denis Carpentier for waterproofing doors and trunk door.
My 48 Merc 4 dr (Canadian model 114X) has relatively new rubber but leaks like a sive

If the rubber is new, you need to adjust the doors. New rubber is pliable by nature, and should kind of bounce back to its previous shape.


Sounds very reasonable, I had kind of assumed some wrong products might of been used here. Therefore adjust first, then fil in any remaining gaps.