I have just completed the knee wall/ crawl space area of our dormer house using the vario air tightness system. I find the Vario protape ideal for attaching the membrane to the timber beams and the masonay wall and I am sealing the overlaps using KB1 tapes.
As the project has progressed I am getting more proficient at installing the membrane. Initially I was running the roll horizontal along the rafter/crawl space area and then running a second roll above it to complete the seal. I have found that it is more practical to run the roll vertical up along the rafters and use the protape and the top and the bottom. I would recommend measuring and cutting the pro tape in a big area such as your hall way so you can ensure you use the right amount. What also helps is to attach the protape to the Vario KM Duplex UV membrane on one side this simplifies the install.
When dealing with masonry walls I run a strip of the protape along the wall and when the Duplex UV is in position remove the other side of the tape and attach. I find the Vario DS sealant impossible to use and its very messy.
The powered respirator is a god send and so is the 60 Watt LED light wand, I would not be able to do the install with out them as you are working in awkward corners with insulation dropping all around you as you position the rockwool flexi in place.
The attic overhead is next and I am hoping/praying that it will be more straightforward ! Time will tell …