Hi carsonsig, The main trunks centered in their SWC you train up a cage will not die from any side branches that get hot spots from them twining into the fence. Any tomato fruit lying against that size steel bar you had better pull away & tie it over elsewhere. If you don't butt the SWC up to the fence it will be better for harvesting & all that growth penetrating the fence won't be inaccessible. Your lake view will be less obstructed too, especially if prune any indeterminate plants. It is always good to be able to get around tomato plants for scouting out developing problems. A horn worm hiding beyond your reach can do serious munching damage. Since the fence is a good stabilizing anchor for the cages just wire tie some horizontal reinforcement sticks/bars on to the fence uprights. You can then integrate the fence's structural rigidity by tying your tomato cages to those cross braces & keep the SWC a couple of feet off of the fence itself.

We did go with Railing works, and recommend them highly! We've gotten lots of compliments in the years since. The color fits our stucco, and the cables almost disappear as we're looking through the railing to our back yard Our experience was very pleasant, and the results awesome. They were knowledgeable, easy to work with. Easy to get samples of color and the top/bottom etc. elements, so which is what persuaded my skeptical DH that this was precisely machined, excellent powder coating, a very clever design, and could be a DIY project. They worked with DH to choose the type of attachments to the deck, and also to the concrete stairs. In collaboration with them, we supplied the specifications for the railing, including all turns and stairs -- they answered all his questions, mailed diagrams back and forth till my engineer husband was certain it was all nailed down. The "kit" came with clear instructions. It did require cutting the top and bottom rails to for some of the 90-degree angles; DH has a circular saw, so that wasn't a problem, though My husband and sons (16 and 10) installed the railings around our deck, and also next to the stairs to our front entrance. I can't praise it enough!

Adding the boards is a good instant fence. A family in our old neighborhood needed a privacy fence in a hurry (something tight enough to keep their dogs from stcking their heads though a fence and nipping teasing kids. All the yards in the neighborhood had steel fences similar to the above photo. The fanily took premade cedar panels and attached them to the metal fence by using lag bolts to attach the panel through the fence openings into a cedar 2X4 on the opposite side of the fencing. This effectively clamped the panels on to the existing fence. They were able to remove all the cedar panels when they moved a year later -- and did not damage or have to put holes in the steel fencing that was up.

Read the Housetweaking blog from early 2011 through 2016/2017 or so. Dana and her husband bought an old, ugly midcentury and DIYed it into a really cool space - keeping the midcentury vibe but not being 100 percent married to it and doing it on a budget. They've moved on to a different house but all the old posts are still on the site. https://www.housetweaking.com/current-house/