short rail joiners, ie not the full length ones yuo get in a pack, cut sgort so not to tsek lot of space to minimise the sleepers cut......
That is about what I would think also. It is a new concept to me since I have never heard anyone suggest cutting joiners before.
For Peco track I normally cut off the seat and spikes on the sleeper closes to the join. That allows the joiner to be pushed between the rail and sleeper, then the sleepers can be slid up to the join to avoid having a fugly gap in sleepers.
My concerns with shortened joiners would be firstly how much use they might be. Let us allow for a moment that the engineers at Peco settled on as close as possible to the most effective length of joiner. Shorten at your own peril, risking vertical or lateral misalignment. A second question is how to shorten the insulated joiners, and at least one end of the turnout you would want to fit insulated joiners (does anyone use Insulfrog theses days? Not me.) The insulated joiners have a divider in the centre, so it would mean cutting a bit off each end.
Anyhow not a big deal, except that I would suggest anyone contemplating cutting their joiners shorter think before doing it.