Here's my thinking about the Juice system: Tying a concrete cost to weapons allows for more freedom and flexibility, especially at high levels of play. For a stage like Big Windmill in particular, the high cost of the uppercut makes routing really interesting and leads to diverse strategies. It does affect those who are starting out a lot, so finding a way to make it more forgiving without taking away that limiting factor is a good idea.
It does make sense that getting the Voltaic ranks can be really hard, but I want those to feel like a substantial challenge. I could absolutely see myself lowering the times it takes to get a potent rank instead so that it serves as a more effective middle-ground and can feel like a satisfying challenge without demanding as much mastery as Voltaic.
For the first note, whichever weapon you bookmark with 'E' is automatically loaded whenever you restart a level so you can always start with the weapon you want. I don't think I tutorialized that well, so that's something I should rework to be sure.
Also, I should have a new demo out in a few days so please give that a try when it releases and let me know if the issues are lessened in that build! Thanks for taking the time to write out your thoughts.