If I ride with English leathers and my toe in the stirrup, then I sometimes get bruising or chaffing about halfway up my calf. The root cause was my lower leg moved too much, and this particular saddle - where it positioned the stirrup bars, the lowest part of the seat, etc - meant rubbing. It didn't happen when riding in my Bates CC saddle.
But I normally prefer to ride with my feet 'homed' - the stirrup almost as far back on my foot as it will go. When I do that, the stirrup strap falls against the shaft of my cowboy boots - and I now ALWAYS wear cowboy boots with a good heel as part of my personal safety equipment. I'd much rather skip the helmet than skip the boot!
Happily, my lower leg seems to be getting more secure. I also often ride with a mild chair seat, which seems to help. DownUnder claims that is what an Aussie saddle is designed for, and I won't argue:
"Riding Position: Adjust the stirrup leather length so when you're sitting in the saddle your thigh runs parallel with the kneepad. You'll ride longer in the stirrup with your feet forward and heels down. You should place 25% of your weight in each stirrup and the balance in the seat of the saddle, this ensures an even weight distribution on the horse's back."Wither tracing and fitment instructions for Aussie Saddles
Also from DownUnder: Australian Saddle Fitment for Rider and Horse - YouTube