I quit buying Duo-Fast tackers. They simply aren't what they used to be. I now use the Powernail version and it has been pretty reliable so far. I have three Duo-Fast ones that don't work. Well, I also have one of those ancient ones with the round head somewhere oot in my garage and that joker...
The bag keeps the filter from getting clogged so it's actually an overall improvement in suction because of the amount of surface are you're using to filter the air moving through the assembly. Maybe not the second you flip it on, but that isn't a valuable metric.
I always use vac bags. The things are pretty much worthless without it. They're expensive, but a shop vac isn't worth much without them. The filter clogs immediately. I use mine for undercutting fireplaces and also for catching my edger. That crap filter is simply not up to that task.
The crummy thing about black walnut is how it bleaches out. Most exotics get more color when exposed to sunlight. Walnut does the opposite. Its weird, you can jump on old, bleached out walnut with an edger and it's nice and dark right underneath.
Geez. Take Fein tool and cut off a piece at the wall. Then you will at least know what you have to work with. Many engineered products have a 1mm veneer. You ain't sanding that. You can't even screen it because one high corner and you need a new floor. Then again, some have thicker veneers...
Now that I have three duo-fast tackers that don't work, I broke down and bought the powernail tacker. (patent pending) I smacks pretty hard and is a little short for my taste, but so far I like it.
Take that for what it's worth.