The ends can be flattened if desired, but keep in mind that slight angles angles are at play in its installed position.
I find your work to be exceptional and it inspires me to get to work on my UP, SP and WP cabooses I've had floating around in my head for years.
I've kit-bashed a few UP cabooses and like yours here, they all have smokejack support wires, and I've tried various methods of representing these very fine wires in a way that both looks good and are durable. Additionally, I don't want them to eventually sag or get bent, which is a problem with very fine, whisker-thin wires of various compositions.
I noticed that on your smokejack, you're using grossly oversized bent wire to represent these supports so, I thought I'd offer a suggestion and a photo or two of what I use and how I do it.
The hardware for my N-scale smokejack support wire is 000000 (6-ought) non-sterile woven black suture silk, which is a bit of a PITA to find, but I bought mine years ago on a wooden spool to represent rat-lines on my 1/8" scale 1800's scratchbuilt sailing ship models since it doesn't fray, ties very well as it's designed to do, and is quite robust strength wise.
I've tried fine stainless wire, ultra-fine Titanium wire, heated & stretched Styrene sprue, and none of them came close to working as well nor as easily as the 6-ought black silk suture. The wires bend and/or come unglued, the stretched sprue breaks...silk suture doesn't need paint (adds thickness), is stretchy enough to that it never sags, ties in a knot on one end to act as a "keeper", not fitting through the 0.007" hole that I drill for it, threads easily through the same holes in the smokejack and down into the receiving hole on the car body roof, where I pull it tight, put a dab of thick CA on it on the inside of the car body, apply a bit of Accelerator (or nowadays, shine a UV flashlight on it), wait a few seconds for the CA to cure, do the same thing to the knot in the other mounting hole, then snip the excess suture off.
Photo (1) - SP C-30-1 Caboose by MTL, Fine N Scale, FVM and me...note the smokejack support wires... 
Smokejacks by UP put the support wire over the top which is also easy to do with 6-ought silk suture.
Photo (2) - UP CA-4 superdetailing project with over-the-top support wire...close up showing complete absence of any fraying in the woven silk suture:
I've had the above project uncompleted for over 9 years...no sagging, no drying out and fraying.
Since I'm obsessed with getting cabooses "right", solving the smokejack support wire problem is something I thought I'd pass along in this thread because of the excellent work being done here.
Cheerio!
Bob Gilmore
