Don't use the .445" round balls and don't patch them. You want a tight seal that only a properly sized round ball swaged into the chamber by the loading lever can achieve. I would save these balls in case you might wish to melt them down if you choose to start casting your own round balls.
You can use .454" balls if you really want to, but it isn't necessary. The .451" balls will provide a tight seal in just about any Italian replica revolver, as long as they are perfectly spherical and pure lead and don't come from an el-cheapo replica Italian mold where the hemispheres do not align well. Any quality Lyman, RCBS, LEE or other quality mold will give you what you need, as well as the Hornaday .451" swaged balls of course.
I own a Pietta Remington .44 now, and owned a Euroarms .44 Remington way back in 1972. In both cases the .451" round ball is a snug swaged fit and is perfectly safe. In fact back in the 1970s and for many years afterward .451" was the recommended ball size for all Italian replica revolvers. The only real exception in fact seemed to be the U.S. made Ruger Old Army which used a .457" ball just to be contrary.
The more recent idea of using .454" round balls seems to be more about being double safe. Pietta also only recommends light powder charges in their owner's manuals, which is lower than the powder charges which were standard in previous years. Neither precaution is necessary.
A .451" round ball and a 28 grain charge of FFFg black powder (or substitute equivalent) is perfectly safe in just about any .44.
In fact, the Remington chambers will hold a bit more, and this too is safe in solid frame revolvers, but unless you are hunting, why bother?
The problem is that .454" round balls require considerably more force on the loading lever to seat them. While this may only be a bit annoying with the solid steel frame of a Remington replica, it puts a lot more stress on the wedge and wedge slot of a Colt open-top revolver replica.
And with a brass frame open-top replica revolver it could contribute to the loosening of the cylinder arbor in the frame.
If you have not bought percussion caps yet, you will find that Remington #10s fit the nipples the best, rather than the more common #11 caps.
However, I have never had any problems using #11 caps. Just pinch them a bit to make them very slightly oval-shaped and they will stay in place on the nipples and fire properly.
Enjoy!