French Horn/light weight/light blowing horn
I've been playing a Hoyer 801 for 10 years now and I would like to buy a new instrument. I'd prefer something (semi)professional over a "student" model. Everyone tells me to go for an Alexander but when I tested them I found them rather "heavy" and "heavy-blowing". I also tested a Willson and found that one much less heavy and it blew much easier. I tested a Yamaha several years ago but didn't like the sound. I want a real nice and warm horn sound, nothing to bright.
What brands would you say are "light", "light-blowing" and have a warm sound?
It's very difficult to generalise about how different horns feel as it's a very subjective thing. Similarly sound differences are much more obvious to you than to anyone else - the difference to the listener between two different players playing the same horn is often more than the same player playing two quite different horns...
So the only real answer is, try everything you can afford, and buy what you like the feel and sound of, but also try to get someone you trust to listen to you play the different instruments.
I think the Willson horns are quite good, although they're not really taken seriously as a professional instrument over here. The lightest horn is an Englebert Schmid but unfortunately your pockets will also feel very light after buying one! They're hard to get hold of but it sounds as if you should try to at least play one. My wife plays a gold brass 5-valve double and it makes a fantastic sound.
There are, of course, different models from the other manufacturers you mention - an Alex 103 is quite different to an 1103, and in the case of Alexes each horn has it's own characteristics, they're the least consistent horns I know. But if you find a good one it's really nice.
Yamaha makes everything from the 667 (quite tight and bright medium bore) to various big and woofy large bore horns. I play a Holton H104, I think it's a great horn, but I've no experience of the more current equivalent H105. A lot of my advanced pupils have Holton 378s or 177/178s. I really like the way Holtons sound. But you probably don't...
So sorry not to offer anything more specific apart from don't bother with Paxman (despite half the pros in the UK using them) or any US horn apart from a Holton.
Hope this helps a little