My Troop Guide gave us guidence on this for each ticket item. Could be a pic., could be a note, whatever was appropriate. For example, I presented a "What Knot-Why Not" game I developed for Scouts at 2 Roundtables (a game with a purpose - luv that!. The RT Commissioner just wrote a note for me saying so. One thing my TG said, I have used as a TG, and told TG's when I was ASM for TGs, was re those ticket items that might be a little more difficult. It was: "A Scout is trustworthy. Scouters should be too. Because of this, when you tell You've completed it, I'll take your word for it". So, I suggest to contact your TG to review verifications - after all, it;s the TG would signs off on your ticket. Hope this helps.
Just an Ol' B'ar riding his ticket...GwaP