Attic flooring

I have attic trusses in my house, so I have an 8’ wide attic running the length of my house. I have enclosed 20’ of it to use as an office/guest room. I made 2x6 redwood tongue and groove flooring, 10’ lengths, finished with a fancy linseed oil. I did it this more difficult and more expensive way in order to not use plywood subfloor, as that stuff is nasty and doesn’t belong in my home.

However. I am concerned about future squeaking, which is why most 3/4” flooring receives an underlayment on the plywood.

Since my flooring is only touching the joists (truss bottom chords) I am hoping to use only narrow strips of some type of underlayment, perhaps stapled to the joist. This is the only place where I am using a raised floor, as my ground floor is earthen. I would prefer to not buy a giant roll of a natural underlayment if I only need a handful of 1.5” wide strips.

Any thoughts? I have some linen scraps from making curtains. Seems super fancy to use something like this under my floor, but it would be free… I want to do it right the first time and never address it again for the life of the floor.

That underlay is not always used for flooring to stop noise.
Some ideas to consider to prevent squeaking;
- used a floor cramp to push the floor boards together.
- run a flexible glue on each joist.
- fasten down with either screws, galvanised nails or grip nails. Bright nails can work out.