lot's of pictures, here's how I secured straps to an ancient Linhoff and a newer Gitzo tripod.
First the Gitzo.
I made this strap and fixings well over 10 years ago and they haven't failed yet, despite the 'recycled' nature of some parts.
I found a strap with the plastic spring catches somewhere, I'm pretty sure they were on a bag that I sacrificed, the kind of thing you can get in a charity shop for pennies.

That's the Gitzo with the strap inplace.

One half of the plastic clip is secured to the tripod by using this 'figure of 8' piece of flexible plastic that is threaded through the clip where the strap used to be.
The plastic is cut from an old gallon container with a craft knife. That is the original piece I made over 10 years ago and it hasn't broken yet.

A better view of the plastic bit. Obviously the holes are cut to suit the size of whatever tripod you have. I used a 'bell punch' but a sharp knife and some cussing will do the job.

The plastic clip in position and secured in place above the centre column locking ferrule.

The bottom clip uses some of the original bag strap with holes punched in it, the edges are then welded up with a cigarette lighter or a candle to stop them fraying.

The Gitzo has a 3/8 UNC thread in one end of the column so a bolt just secures it in place with a couple of washers. I leave it finger tight so it rotates, and use a long bolt so it wont fall out.
The Linhoff, my favorite tripod and an old classic so I certainly didn't want to hack it about, as I didn't the Gitzo either.
For this I made a couple of aluminium brackets, which being an engineer and having a workshop isn't a problem for me. But these kind of brackets could easily be made from plastic with basic home tools.
The bracket.
In position. There is already a rubber O ring on the column to stop it banging when you put it down, I added another above my bracket to stop it rattling around.
The bottom of the column has no threaded insert like the Gitzo, so I used a butterfly clip that is used to secure things to plasterboard walls ( sheetrock ? ) It's the spring device that you insert through a small hole and it springs out and secures behine the board.
Here I use it to secure inside the tube, so it might pay to just sharpen the tip of the clips to dig into the inside of the column tube, the Linhoff has a machined rim that the clip secures to very nicely, but not every column will have that.

The end of the column needs a blank with a hole for the screw to pull against the spring clip, I have experimented with a few houshold items such as bottle tops and they work ok. The picture shows a proper tube end blank ( stolen from an office chair ) that I pierced a hole in with my multitool.

As stolen from a chair.

Making a hole.

The assembled clip and bracket.

Inserting the clip and bracket.

Tightening, but once again I leave it loose enough to rotate.
As carried for miles.
I hope there's a few ideas there, I bought a strap that 'in theory' you can tighten around the legs, but the 'theory' doesn't work and I became so frustrated that I went the DIY route.