What you appear to have is a "lantern" post, which I happen to consider are nearly worthless for any serious purpose. "Nearly" only because once in a blue moon it might reach somewhere you need to reach. So far I have had the moon stay stubbornly white for 15+ years. There might be one of those posts in a drawer somewhere around here that I have forgotten about, but I don;t use them..
For my purposes, a 4-way post has been more than adequate, although I do use some various block type and other holders for boring bars. I have done mostly one-off prototype and minor tooling stuff, repair parts, etc, very little "volume" type production, and even that nothing over maybe 50 or 75 pieces, as a rule. That's a lot like the usual home shop person.
You can spend a lot on a "really good" QCTP, and then a bunch more on the holders you need to make the "quick change" actually helpful, since you may want as many as a dozen or so holders for various cutters, cutoff tool, threading tools, maybe a knurling tool, a couple boring tools, and so forth.
And after you get all that tool holder stuff, you still don't have tools. If you are going to operate a shop for profit, you want a good QCTP and plenty of holders. For your purposes, you would do fine with a plain "block" type holder that holds a single cutter. Standardize on one size, and grind them so the cutting edge is at the top, and you can make your block holder hold them all at just the right height by making a "filler block" to go under the tool.
Save that money for other tooling, and the mill you will be wanting.
In fact, you can use that "lantern" post in a reasonable way.... Make a ring that fits over the center post section. Make it just as high as wil hold your standard cutter size right on-center when they are set on top of it so that the screw in the post holds the cutter down on the ring. If you are lucky, you can just flip over the existing ring to give a flat top surface at the right height...... Now, put all those holders in a drawer, along with the little "rocker" piece, and the old ring if it isn;t the right height.
The cutter clamped on the ring will be way more solid than the usual lantern holder, and will, if made right, always put the top of the cutter on-center where it needs to be.