Hayseed,
You will be fine with a 28" .45-90 in BPCR shooting.
There is some interest in that length for metallic silhouette to make it easier to manage for the offhand chickens. And it will not take much off the sight radius for the prone/cross stick targets.
For any form of target shooting I would substitute a globe front sight for that blade, the Soule rear is just what you need.
To keep the kick down, you could try Fg powder.
A good recoil pad, either a Rand or Pact wearable or Shooter's Friend polyurethane slip-on will be a big help.
I don't know current prices, that is probably not out of line with good rear sight and dies included. Anybody else's ammunition has to be considered garbage to be recycled for the brass and lead.