I used some Feeney products MANY years ago...like 15?..before they had their kits and speciifc deck products. When you could drive by, and pick up parts yourself over at their warehouse...
Seems WAY too expensive now- they sell to the middleman, who sells to you.
Since then I've just bought materials. On a few occasions, I've had ends machine swaged, but I also have a mechanical crimper. (Machine swaged fittings look better.). Depending on the design, you can often place the field crimp at a less visible location. Or use the automatic ends with the internal jaw/clamp.
I just did an architectural wood item- a large 9 ft curved oak 'arm' that was suspended out over a second floor railing- used two 1/8" cables to hold. Found all the fittings online, outfit in SoCal. Turnbuckles, clevis fitting, etc. There are quite a few vendors- some for just parts, some with a 'deck railing focus', some who will fab ends for you. Way less than Feeney
Finally, on the horizontal thing and kids... Ever see those nanny cam videos of the babies supposed to be sleeping? But instead they are up over the
vertical railed sides of their cribs like Olympic pommel horse champions? tell them not to climb it. Monitor them. And hey, it's a way to weed out the dumb ones. (

)
Finally, vertical cables increases the cost exponentially, I'd think. I can cover 80 ft of railing with 10 cables. That's 20 ends. Vertically you would need two fittings every 4 inches, 6 per foot, 480 for 80 feet. If my math is accurate...