Correct - that really works well for several of us.
No, I have not shot the 445 at all. I did order some Bull Shop 350 grain lead conicals and shot them. they shot really well. I thought I might use them on deer. But, I remained with the 400 for elk and deer. It really is to big for deer, in my mind.
Yes, I started out with the 460. But later found the 400 worked equally well and it had flatter trajectory.
I use Montana Xtreme Bore Conditioner on a bore snake as the final step in cleaning.
Another thing I do and works very well for me - Wrapping the breech plug
Another thing you might want to do is create a bit on a stick for cleaning the flash channel in the breech plug. Use a 5/32" drill bit. You will find that you can build up a carbon deposit in the flas channel.
Hope some of this helps a bit.
I love questions! Especially if I can answer them!