Stop trying to fix two issues at the same time. Work on one at a time. Take the uNI out, put the paper back in. Swap out later when you're done tuning.
Get the mains sorted out, then dick around with the medium and idle throttle positions.
Stuttering is probably caused by being too rich, try your stock 110s with the thruxton needles. If it helps you are closer to the ballpark. Go up in main size until it doesn't help, then back down one. No shims with the Thruxton needles either.
Also check your uNI is not opveroiled. That will also cause your problems. Try it with the stock filter until you get it dialed in, then go back to the uNI.
