On Wednesday, August 29, 2018 at 11:26:18 AM UTC-4, wrote:
Is there anyone that knows if an Blanik L13 open trailer will work for an L23?

Not without fittings being modified. Any open trailer can be made to work with just about anything given enough time and talent with welding. The same open trailer in our club has supported at various times an L-13 Blanik, a 1-34, and a Pilatus to name a few.