Glad it's resolved. We can all use help, someone on here has had the same issue. Post-up, and here come the inputs.
Back in the 'early days,' my first bike was a 305 Scrambler I bought off a college dorm mate, he'd bought it new, and was not riding it. Not many miles, it needed some work, so I got it pretty-cheap. It came w/a new paint job on the tins, done by a friend who owned an auto body shop, and it came out absolutely beautiful. It cost me a case of beer, and he used some leftover paint, which turned out to be an orange/red.
I learned a lot about offroad riding on that bike, and I used it to commute to work in MI which is where I was @ the time. I also learned a lot about mechanics, and putting my Montgomery Wards 3/8" metric socket tool set my Dad gave me as a teenager to good use. I still have it, and still use it, though the ratchet broke and was replaced, and a couple of sockets had the same fate. Anyways, one of my friends taught me about using a sewing needle or the tip of a toothpick underneath the throttle slide and then adjusting the throttle cables so they moved together, and starting from the same opening. "Just see that they both move at the same time when you begin to open the throttle," he told me. It's worked for the last 40+ years on a variety of bikes for a static adjustment. Whatever you have that's a thin gauge will suffice.