A few months ago, I started a thread about using a long stroke dial indicator to indicate carriage travel on my lathe. I bought a 2" stroke dial indicator, but as I got deeper and deeper into it, I came to realize that nothing actually beats a DRO set-up. So, I spent some of the Rupnow fortune on a nice DRO set-up and installed it on my lathe. It's wonderful!!! If you have the money to do so, then by all means buy one. They are worth whatever you have to pay.--However, that left me with a 2" stroke dial indicator and still no way to accurately monitor the travel of my tailstock quill. Today was one of those rare days when I had absolutely nothing else to do, so I made up a bracket and installed the dial indicator on my tailstock. I even got real fancy, and made a video of it working. It wasn't until I replayed the video that I realized I had said "2" DRO" instead of "2" dial indicator". Ah well, bad on me. I'm not going to make a new video just to get the wording right.
Does your tailstock have a self ejecting feature? If so, when you fully retract the barrel does the retract feature still work with the bracket fitted?
The reason I ask is that I fitted a digital scale to my tailstock but had to counterbore the bracket by 50% to permit the barrel to retract sufficiently for the self-eject to work.
Going this route still allowed a good clamping on the barrel. The ball/socket joints permit the barrel to rotate (in case of any wear on the key - there isn't any at the moment) without straining the scale.