Need Tips for adjusting to boosted H3

For your first and second points - without knowing what your stroke actually looks like - it sounds like you are not generating enough spin (and consequentially arc) against the defender.  Coming from MXP or almost every non-chinese rubber, this is usually because you have not become accustomed to the harder sponge of hurricane (especially the original and non-neo sponge) and previously relied on the tensor/cake/tenergy style sponge for spin generation rather than topsheet brush.  Chinese rubbers on average need more racket speed because they do not have the same elasticity of euro-jap rubbers, so focus on committing to your swing and over-emphasize the followthrough for now until you start landing your loops on the table.

For your third point, I've had similar problems in the past with blocking using Chinese rubber.  You need to influence the ball in some way - especially if it is a high quality slow loop - in order to return it well.  Because the sponge is relatively harder than what you were accustomed to, a ball with little forward momentum will not engage your blade or sponge and will slip on the topsheet if your hands are too soft.  Try to employ a slight roll or topspin against your partner's loop until you get a better feel for the rubber.

With H3, hitting through spin is not as easy as with most other non-chinese rubbers.  You are almost required to spin or counter the ball back - I cannot think of any high-level user of H3 that hits or soft blocks slow spins with their FH... almost all of them counter or roll the ball back.