The same nipple wrench will work for both rifles. Unless the nipple has been over tightened, this wrench is my favorite
http://www.dixiegunworks.com/product_info.php?products_id=14494 You can also get a socket that will fit musket cap nipples if you ever get a gun that uses musket caps.
If you have a nipple that needs the extra oomph to break it loose, this is what you need
https://www.trackofthewolf.com/Categories/PartDetail.aspx/65/1/NW-120 In use, the length of the T wrench will cause the hammer to be in the way and you will have to remove your hammer in order to get the nipple out. It's a simple task but a necessary one.
The first nipple wrench has the advantage of being a ratchet wrench and is very good for everyday use. But, for those really stuck nipples, I reach for my T wrench like the latter one. I have both but use the ratchet wrench most of the time. But, there are times when only the T wrench will get 'er done. If you can afford both, get both but if you can afford only one, get the T wrench.
If, in the future, you get a rifle that uses musket caps, you will need to buy a musket nipple wrench and if you get a cap and ball revolver, you will need another wrench for revolvers. There are different wrenches for different revolvers so if you ever need to buy a revolver wrench, be sure to get the correct one for whichever revolver you have.