If the forearm has points, it makes sense to do it on the forearm.
If it has no points ( specially if it's cored) you can tenon to the handle.
I use a 14"+ core and go to the handle
I prefer XX/paper on my torrified maple shafts.
Canvas is rough on the radial taps and live threader.
Canvas is good for one-piece ferrule tip breaker and collars and caps though.
Just like any material now, you also have to pick the best pieces if possible. Not all phenolics are the same..I...
The longer the wood, the more warp prone it is . Joining two cores is more stable . Plus it gives you the option of adding weight at the neutral area ( middle of the cue ) .