It's a mixture with features from 7.4 to 7.7, but yes, the base map is 7.7
First we were thinking of having runes 2x except for a few runes like SD, UH and Magic wall. But we're open for discussion regarding this
Weight/capacity is an important aspect in balancing the game. I think it's a good idea to keep the original weight balance. However, stacking runes became obnoxious. It would be nice if they worked like gold coins for example. I would prefer having a bag of each rune, personally. Perhaps they could be limited to stacks of 20 for nostalgic reasons? Multi charged runes could also be capped at 20x stacks, with weight balanced accordingly.
Maybe it's taking it too far? The feeling of seeing your current backpack going empty in a pressed situation is nostalgia too.