The rope I use is something like 2.5mm in diameter...maybe 3/16 inch or so.
Some people start at the bottom and work up. I start at the top and work down. Just take your time. You may be surprised how fast you get the hang of this.
You will see some instructions to apply sealer first and then install the windshield. That may have been okay when 3M still made their non-hardening sealer (08509 I think was the part number). They stopped making that and all you can find today is stringy, sticky and really messy, so I would never apply that first. You'll get it everywhere.
I would install the windshield, adjust carefully in the bends/corners, let it sit for a week or so in the sun.
Then I'd get some high quality masking tape and carefully tape the cab right next to the weatherstrip and tape the weatherstrip edge also.
Then use a ball hook tool to pick up the weatherstrip (outside edge first) and on a cool morning use a caulking gun to squeeze it in the gap. Clean this up with mineral spirits or WD-40 (some people say it works well) and after it dries as much as it will (not a lot) then use some urethane sealer to seal the edge of the weatherstrip (outside where it meets the glass).
You'll probably need to use masking tape to hold the corners down to the glass while it sets but please understand you have to work quickly. That urethane stuff dries fast. I usually have my helper follow me around taping the rubber to the glass. When that dries completely (maybe 8 hours), remove the tape carefully and slowly starting with the tape that is on the weatherstrip.
Some people like to use silicone on the weatherstripping that goes between the cab and the rubber but it isn't my favorite. That stuff dries with a real high shore rating (hardness rating is what that really means) and these old cabs are known for flexing and twisting. I prefer something in there that can take a bit of movement.
