Your HR link is a very traditional mouthpiece with a large chamber, swimming pool baffle, and large bore, it's the antithesis of a MBII or Dukoff D chamber. Tip openings on HR links need to be modest because it takes a lot of air to fill the mouthpiece up. You might be surprised to find out that your 8 Link is actually a 105 or smaller tip. Modern Links are usually undersized a good deal. Sizing charts are almost worthless when comes to a JJBabbitt.
Your metal link was a smaller tip and more than likely needed a stiff reed to keep it from clamping off due to the increase of air pressure needed for high notes and altissimo. Better off with a 6, 6*, or 7 as they won't have that problem as much as long as you play a reed that is hard enough.
Basically the MBII is a low resistance piece. It has a small chamber, wedge baffle, middle of the road sized bore and a square chamber all designed to make it blow without much effort on your part. The hard part is controlling such a set up as it doesn't have the built in resistance of a link and doesn't offer you anything to push against. It's like going to the grocery store in a drag car at 220 mph two blocks from your home, it's over kill in so many ways that it doesn't make sense for anyone to use it unless your a seasoned veteran or perhaps Michael Brecker that needed such a piece because of his throat surgery to reduce back pressure that would have been caused if he'd used a larger chamber piece such as a Link without any modifications.
In the end the tone suffers from the use of such souped up mouthpieces. Coltrane, Pharoah Sanders, Rollins, Dexter Gordon, Chris Potter, Bergonzi, Eric Alexander, Wayne Shorter and the list goes on and on of those that used the traditional Metal and Hard Rubber Links in their careers and achieved a beautiful sound. Many feel Breckers sound was much better before he started playing the DG pieces....including myself.
Resistance can be cut down with a good facing and the right tip opening. Metal Links once you get used to them aren't nearly as resistant as you'd think and the tone is oh so beautiful compared to these more contemporary designs that seem to attract a lot of attention.
