This is the 2nd thread where we’ve given you input and you’ve gone back to saying Bjorn uses the tube wrapped wire tourniquet method and that’s what you’re going to do.
Why not try a number of methods? Use the wire tourniquet method (because like you’ve mentioned before you’ve already bought the wire and tubing), try some seedlings through a washer/tile, try air layer a group of branches. Try them all if you have enough material.
I’ve got 2 groups of 3 seedlings through washers (1 in a grow bed and 1 in a pot), 1 group of 5 seedlings planted really close together when they were only a few months old, and a group of 5 branches from the same node that I layered earlier this season. I’m trying them all. Not to see which is “better”, but because that’s just what I tried in each scenario. With enough material you don’t always have to be searching for the “best” way to do something, but can simply experiment and try different methods. They will all produce pleasing trees if executed properly and developed accordingly with proper technique along the way.
Like others have said, there’s no best way that will instantly give you a perfect clump within a few years. They are all just techniques to start the process. From there’s it’s just up to proper technique and basic fundamentals to continue the development towards your end goal.
I appreciate it may be difficult if you’re young and have limited material, but try not get fixated on finding the single technique that will best utilise your current limited resources. Try one technique with what you have now and then try something else the next time. Cresting bonsai should be fun and somewhat free form, it’s not an exact science.