I just finished weaving a couple of these scarves using the kit (English Rose colourway) and thought I would review my experience. This is not the first time I have used the 40/2 linen, but the first time with a floating selvedge (I think). I have never had issues before. Weaving on a David.
For the life of me I could not keep the left floating selvedge in tack. I tried the flour/water method, the non-weighing vs weighing method, I did not spray the cloth with water, I did keep a good angle, I wove slow and steady (but not too frightful). Didn't matter. Something in my method kept causing the selvedge to break. The right floating selvedge held through the entire 6 yd warp. As did all the other warp threads.
After about 12" of weaving I decided to just chuck it all in and left the left floating selvedge off. I trimmed the thread after finishing. I planned all the canvas weave picks to go towards the right. That did mean that I had a couple of doubled up thread tucks but that was resolved by letting one end hang out, the other tucked. All trimmed in the end.
Scarves are gorgeous in the end. I am determined to master the linen issue as I have many plans. I am thinking if I use silk weft in the future, perhaps I use an additional silk floating selvedge with the linen one. Same with bamboo or tencel.
Forgot to mention: The weaving draft that comes with the kit does NOT include the floating selvedges in the end count. I did not do any maths beforehand and assumed they were included (as always in the weaving school kits). So add 2 ends to the count if weaving by the kit draft (= 334). Or I'm a dunce and can't count! My scarves were 2 ends short on the left side RE design, but that doesn't matter one tiddle.