Funny you should post that about this rig in particular. His father drilled out the hole to 5/8" and was worried that it was not a perfect hole. So, he machined up a sleeve to make it a perfect precision fit and pressed that in. Unfortunately he made the sleeve ever so slightly too long and guess what happened? That's right, it wallowed the sleeve out since the hole size for a bolt makes just about zero difference within reason. It is only the amount of clamping force you can develop on the faying surfaces. But, only you would bastardize that into me recommending using a tapered pin in a straight hole. If you can't make the normal crap work then you have other issues not related to bolt size versus fastener size. And I have never said no matter what the hole size is. And again, you have yet to explain how the slots in the front lower control arm mounts work if you believe that drivel you just spewed.
I have fixed several stock track bar mounts with tapered inserts that have a shoulder to convert them back to the stock taper.