I agree that too many topics for a 1 hr presentation. Knots can easily take more than an hour just to teach a few. I would save that for a seperate presentation. A PSK would be one way to introduce survival and light weight backpacking as a similar topic if you feel you need to present both.

For lightweight backpacking, you might arrange for someone in the troop to bring their normal backpacked for an overnight. You bring along your lightweight pack packed for an overnight. Allow several boys to try on the two packs and feel the difference.

Break open the packs and begin showing them some of the tips and techniques you have used to reduce weight. Here is a standard metal mess kit with pans, pots, cups, etc. Here is the single cup and spoon for lightweight. Pass around the two items so they can compare.

Ask Questions! Get them involved. Lecturing to them will not hold their attention. Ask for their ideas on ways to save weight. Be prepared to show examples of ways to save weight (above). I remember when preparing for Philmont, they suggested cutting half the handle off my toothbrush to save weight. That stuck with my sister and she still talks about it 25 years later.

Tarps vs Tents. Bivy sacks vs tent/sleeping bag, Dehydrated vs Canned, Purificaiton systems vs carrying water. Lots of examples that are hands on, easy to see, touch, immediately recognize a payback in weight and that they can use next time out.

Also recommend reviewing the merit badge and rank requirements so you can steer your presentation towards the BOYS goals. Both are available on line for review. It would be great if you could actually be able to check off a requirement for a merit badge or rank as part of your presentation. That way you add immediate value to your customers.