Err yea patience is vital. can get a bit frustrating when a bit doesn't stick down quite how you'd like.
I'd probably say it took a couple of hours. Not including removing and replacing the headlining.
Pull all old stuff off. Clean off the horrible orangery spongy stuff off. Then fit your desired material.
Make sure you use high temp spray glue makes the job much easier. Think I used 2 cans in total.
Start from the front as it's the hardest bit and work your way back doing a small bit at a time.