Not saying this is a perfect way to solve your problem and it seems the dev is already working on implementing a solution, but one way to generate MC H-value between days is to ogle your roommate. Before opening the shop for the day, select "Talk to Cassia", then the top option, then the top option again. If you line up your cursor correctly, you can just spam click and gradually fill the bar. Not engaging, fairly boring, but pretty quick. The amount you raise the H-value of characters you *ahem* interact with is directly related to the drop in H-value of the MC. If less H-value for the MC is available than would be transferred by the interaction normally, it just transfers all you have. So keep that bar full in between days to maximize leveling townsfolk.