I don't ride endurance. But since no one has participated in your post, I'll put my 2 cents worth. I think the main difference you will find between a western and a western endurance, is the absence of a horn. Probably a difference in the stirrup leathers, also. But if your main concern is weight, go synthetic.

 

I am a casual trail rider/hacking around rider. I want to switch from a Western Saddle to a Western type endurance saddle.

My horse is a medium sized 15 hand TWH.

I am a 57 year old more plus than minus sized rider. I am returning to riding and I’m not overly confidant.

A lesser weight saddle would help me a lot as I have to transport saddle back and forth and also it’s getting harder for me to tack up with my heavy Western saddle. I also have a hard(er) time getting my leg over the cantle.

I would appreciate any and all advice as far as brands to look for and various and sundry details I should know.

I have many questions such as what is the difference between an English and a Western endurance saddle.

I think Abetta makes a gaited endurance saddle model. Or I should say did, since the company closed down production, but the saddles can be really easy to find if you look on eBay or something like that. I’m not sure if Fabtron does (I know they had a model with a horn) or if Big Horn does. Of course, you could always buy a regular western synthetic model and have someone saw the horn off.

Here‘s a picture of my Haffie wearing his western endurance saddle. It’s lightweight, and I don’t really like horns on my saddle (especially because I’m a bit of a history geek and the thought of going out like William the Conquerer wasn’t my cup of tea). It‘s not an Abetta, but was made by the parent company of Abetta, so it’s sort of like a redheaded stepchild Abetta. My main saddle is a treeless saddle, but I use the western endurance when I’m ponying my mare.

 

The difference between an english or western endurance saddle is the tree. English endurance saddles have english trees and panels, while the western endurance saddles have a western tree and gullet.
It would probably be helpful that you already know what size western tree fits your horse, based on your previous saddle.

There are quite a few brands of western endurance saddles out there. If you are looking for lightweight, my friends like the Big Horn synthetic endurance saddles. I've ridden in them and they are comfortable. The synthetic saddles from Big Horn or Abetta weigh about 15 lbs, which is much lighter than most western saddles.