Well gee... who stole my Karma?
What'd I do NOW??
I am sure I couldn't have offended anybody this time??! Guess that's the Brits for ya huh, just too darn sensitive...
(heh heh, ok, now I KNOW some sneaky individual will steal my Karma for that, but I just couldn't resist!

)
Hi Lottie, rider position is something I seem to have a lot of issues with, esp when so many UK (and US admittedly) trainers are teaching the "feet shoved home, sit on your pockets" style of western...and then there's the feet forward to stop etc...
I am going to lose even more Karma for this...
The most important thing I can say to you is it does not matter what shape of leather is between you and your horse... what matters is how you can make it easier and more comfortable for your horse to carry you and do whatever job it is you want to be doing.... so, obviously, you start with a saddle that fits as well as possible...
Then you need to look at yourself as a rider... just like on a bike, if you lean, the bike leans, if you slouch, it can be harder to balance and so on... it's the same on a horse, and in my most humble opinion, which on this I flat out refuse to be wrong about

I say that correct posture in the saddle applies to both English and Western riders namely ear-shoulder-hip-heel-ball of the foot on the stirrup. (cutters and gamers are excused from that last part)
It's a fact, that you are better balanced with your feet under you, try walking with your feet out in front?
Its a fact, that even ropers need their feet under them, or they cant stand up to throw the rope... try standing (no hands) in your saddle with your feet out in front...now if you managed that, pretend to swing a rope around!
I mean, I know some of the reiners say they need to put their feet forward to stay on in a slide etc etc, but look at the likes of Gricha Ludwig (& other top reiners)... he stays on his horse just fine, and you barely see him move the whole run... yes, your weight needs to go back in order to not go over your horses head in a good stop, but your toes don't have to anchor you by wedging in his nose...
Its a bio mechanical absolute that if your legs hang straight down the sides of your horse and your feet form a stable platform directly under you, you will be better balanced and able to keep your center of balance closer to your horses, thereby making the whole thing easier on your horse and safer/more comfortable for you.
Give somebody a piggyback ride... get them sat high up and central and still... everything's good right... now slide them down a little... to the side a little... now get them to wriggle side to side "using their legs" - if any of you recall my crash and burn with jockey Christy at the Hand... you'll know that it's darn tough to stay in a straight line with somebody on your back that isn't working with you...any motorcycle riders out there? Ever taken a passenger that didn't kow to lean with you on a turn? Same thing.
Anyhow, as for saddles, yes, I am a nightmare when it comes to saddles... I have ridden English
and western forever, and I like my legs under me, and so does my horse! In fact, Mol has so many muscle issues sometimes, she just can't lope if I am not able to lift a little weight off her back, which I can't if my stirrups are too far forward.
Same for young horses, how can you lift the weight off a little if you are not in balance... and yes, I have seen some out there do it in a saddle I think is set wrong, but you know HOW they do it...? By tipping their hips forward and pulling their legs BACK and then they have to lean on the swell to stay there...and is that good for the horses balance? I doubt it... at the very least is it good for the saddle... not sure, but probably not long term.
The Pullmans - I think you can slide, with a little brute force, the fenders back a little, and if I remember right, they aren't too bad at all, you need to make sure your fenders are turned properly so the stirrup hangs at a right angle to the seat, then get your saddle on a good stand and look at it from the side, then you'll be able to tell if your able to sit correct or not... if you are, then it's your position you need to work on, if its the saddle... you may need a different one. I am sure I remember Andrew Fox telling me he loved the Pullmans because he could sit right in them, so I think you should be OK with a little bad habit busting.
It really does not help when the big name riders are trashing the look of the sport right now with yet another bad fad... look at the top AQHA pleasure riders now,(I HATE the slouchy look they are adopting now... how does THAT make the horse look better?), and 5 yrs ago, 10 yrs ago... it changes every so often, but the equitation/horsemanship riders... they don't change, and THAT'S the way to sit on a horse. But remember too - don't equate "straight" with "stiff".
Ok, I am going to post this now, went off on another rant as usual... sorry! Hope I helped, alittle?! I rambled so much I probably lost the plot completely!