Don't quote me on this and I don't know if it is in stone. You are correct, there will now be an index, not sure exacly what they landed on, 10. 50 is probably close. Reason being is to get more trucks in pro street that can be competetive to help grow the class. As more trucks come on that can run the times, the index will be flexible and adjusted accordingly. In addition, there will be a quick 4 for the fastest 4 qualifiers, which will not be indexed if I'm not mistaken as qualifiying is based on fastest times, not the index. This will give the really fast trucks a place to get it done.
As for removing weight limits, this was in the interest of allowing more trucks the chance at making the index and safety. Lighter trucks are safer, and require less power to go fast which also lowers attrition = more trucks will qualify. Also keep in mind, the rest of the rules in the class remain the same which requires the vehicles to be trucks. So you won't see any camaros with D max's in that class, just lighter trucks. I sat in on this meeting in Texas, and the competitors voted on this stuff.
Craig