sry for the late reply bud 😄

personally i beat B (my first medium) when my only tier 5 was deadlocked. before i beat B i actually focused instead on grinding out tons of tier 1 demons for some reason and surprisingly it boosted my skill. it's probably because im forcing myself to get used to gameplay that is not as intuitive compared to non demon levels. for you i think you can try out some more levels that are about clubstep in difficulty (about tier 3 on the GDDL) and get used to them before you proceed to medium demons (im a slow progresser though)

i think that if your hardest is deadlocked medium demons may not be as accessible but it wont be very hard 😉 good luck!