Hi, keeping little ones on board requires more than netting, strict discipline at the start is necessary or they will climb. A harness
won't stop them climbing either, but will inhibited there movements. Training is essential.
I can't post images, but here links to several showing our netting:
We used ordinary fish netting and lashed it with polyprop cord. I was actually quite sad to see it go as the netting caught the sails, and anything else dropped on deck.