Craggus, Ive used a triple extension for years. My first ladder for everyday use was a triple extender. Part of The first one now serves as the rack to carry my trolley containers.
This first one had a stabilizer bar fitted on the bottom.
I subsequently bought one made by Lyte. I found this one vastly superior to the Youngmans. The Lyte has D rungs. The first thing I did when I got it was to fit a large aluminium stabilizer, this has feet made from car tyres each side of it. I never trusted those plastic/ rubber things they fit as standard.
If your handy with the tools this is how you fit stabilisers.
1] Take out the rubber feet that come as standard.
2] Make two pieces of hardwood that push fit [I had to hammer mine in] and push them up inside the ladder as far as the first rung.
3]buy a piece of 3 inch by 1 inch heavy aluminium box section about 3 ft long.
4] cut out a 1 inch by 3 inch slot in the middle of the stiles to take the aluminium box section, leaving the hard wood in place.
Best to cut it a bit small and use a course file to ensure a good fit.
5] drill 8mm holes through the ladder and box section, put bolts through and tighten up. The hardwood inserts prevent the ladder sides from crushing.
6] cut two pieces of rubber out of a car tyre about 7 inches by 4 inches.
7] Using G clamps, fold the rubber over the end of Your stabilizer, secure and drill two 8mm holes in each piece. With the G clamps still in place insert two bolts with large washers and tighten up. Repeat this on the other side.
Job done. You have rubber feet that are in contact with a much greater surface area.
When you set your ladder at the normal angle and get on it, you have a rubber feet that are behind the ladder. you can pull rubber as we know when using a squeegie. See what happens when you try and push it.
I have never had a ladder slip back on me with this arrangement.
The top end of my ladder goes to a point. This too was an adaption. But Ive rattled on long enough. Second floor! Watch out for those nasty, sudden gusts of wind. DAI