All new Ranch Mini's are going to be the heavier tapered barrel, or The Tactical with an even heavier barrel. All Mini-30's ever made, from day one, have a heavier (.625" barrel) and those do not have the stringing and accuracy issues that the older Mini-14's did (.560" "pencil" barrel).
I have three of the Mini-30's, all 189 series, and they are as accurate as all get out.
I just did a test yesterday to see the difference in barrel length affects velocity.
There was not much difference at all between the shortest 16 1/4" barrel, and the longest one at 18.5 inches. Less than 50 fps. with PPU FMJ. My favorite handload and the Red Army Standard Russian HP actually were much faster out of my 16 1/4" barrel than they were with the two longer barrels.
Granted, the 7.62 x 39 cartridge is not as high intensity as a 5.56mm, so velocity loss is not as great.
IMO, the Tactical would be the way to go if in the market for a new Mini.
Shorter, heavier stiffer barrel, and factory flash hider, all will contribute to better accuracy, less stringing, and less heat build up.
Here is a link to my thread on perfectunion: Velocity Loss Vs. Barrel Length in the Mini-30 - Shooting Sports Forum