ditchdigger,
never having fired a 445 I cannot say for sure but, I'd venture a guess the recoil will be the same. The felt pulse from a 45-70 might even be less because of greater case capacity, thus more room to expand and a less "sharp" recoil.
The Buffalo Classic I had really shot the 300's very well and it liked the 400gr speer VERY well. Less than 3/4" inch at 100yds with tang sight. Not sure if I could have done better with a scope but I plan on adding a 45-70 barrel to my Ultra this summer.
I don't think you'll regret that barrel.