In my case it didn't matter where the outer screws were adjusted. If the center screws are off by even a little bit, it just won't work right. But you are absolutely right. Check the outer screws first.

And my 2-3 shift is very precise/predictable, hits hard, and the tone is very noticable. Much better than the 1-2 shift which I thought was good.

On a side note it would be a great time to replace the center grease with Kyosho 500k diff fluid, or at least Associated 300k diff fluid. I would not use silly putty, as it is not a lubricant, and could break down, and wear out parts. Getting the screws out will be a challenge, some have baked the diff, others have used a soldering iron on the screws to break up the thread lock. I used a 1/2 in drive socket with about a 1" size to set it on, a hammer, punch, and a few good allen bits and torx T10 bits. Then replaced the screws. It was work and took a while, but I managed to get them all out of one side. I only have Ofna 120k diff fluid now, and it helps a little, but it needs much stiffer diff fluid. In racing 300k-500k wins races on big trucks for center diff fluid. The small blocks seem to like 300k-400k, so hands down 500k for this beast.

Damn I love my truck!!! It's cooled off by now, time to run her again.