You can treat that the same as the tile. You can bury your cut edges in the corner and have the factory edge as the show end.

If the factory edge is excessively sharp or has a bit of a burr on it from the shearing process, you can take that down with a delicate application of a hand file. If you have to work it at all, work it as little as possible so the sheen on the factory end matches the sheen on the show face.

If you want to get fancy you could miter the end and return it to the wall, but it'd be a mighty small return. I'd advise against that unless the grout behind the strip really bothers you. It shouldn't as you'll have grout showing behind the tile. If you do a mitered return, don't overheat the metal or you can discolor it.

mongoct:

If I go with the non-miter solution, it seems like I would have a thick exposed section of grout behind the profile. The grout would run for about 1/2" which is the width of the profile, and it would come out from the wall about 1/2". At the tiles, it would only come out from the wall 1/4". If you think this will look fine, I will do it this way.

If you have any close-up photos that show what this would look like, please post.

Thanks

First, I owe you an apology.

I didn't catch that it was "U" shaped, or hollow, I thought it was a solid bar.

Hopefully this will work.

If you can, nip two 45 degree cuts in the top and bottom flanges of the material. The two 45 degree cuts on each flange will met to form a 90 degree angle with the point of the angle right at the back side of the 1" face.

Have them meet a tad over 1/4" from the end of the trim piece, say 5/16ths-inch from the end of the trim piece. You'll lose a little metal when you make the bend. So the "point" of the two 45s will meet about 5/16ths of an inch from the end of your trim piece.

Now grab the face with a pair of marr-free pliers and bend the face back to form a 1/4" return.

I wrote "1/4-inch return", but you can make the return as long as you need. If you tile is 1/4" thick and your thinset is 1/8" thick and you want no thinset to show, then you'll need a 3/8" return. Add 1/16th and make your cuts 7/16ths from the end of the trim piece, again, planning on losing about 1/16" of metal in the radius of the bend.

If you want the return to be the same size at the tile is thick, then make the cuts 5/16th" from the end, when you bend it you'll have about a 1/4" return.

Make that return bend, THEN cut your trim piece to length on the end that'll be at the wall-wall corner. That way if you mess it up you have suitable length to try again.

See my very rudimentary schematic below. This is sort of what I'm talking about. Try to imagine that you're looking at the piece from above as it'll be installed in the wall. The "X"s are the flange. The show face of the material is right below the X's, it's the underline.

The two slashes show the two 45-degree cuts that form a 90 degree angle, the material between the slashes is removed.

XXX\/XXXXXXXXXXX

Now fold back the part made up of the three X's 90 degrees so the two slashes come together and it'll resemble something like this:

[X
[X
[XXXXXXXXXXXXX

I hope that makes sense!

mongoct:

Makes perfect sense. I will give this a shot -- on a scrap piece first to get some practice.

At the inside corners, should I butt the two trim pieces up against one another? Or, do I leave a gap between them and fill the gap with caulk just as I would fill the gap between tiles at the inside corners?

By the way, no apology needed.

To prevent water intrusion I'd leave a gap and caulk it.