Def have a good buffer amount for each project! For me, I had a short but already completed novella that I was able to piecemeal and publish in its entirety(8 parts with a weekly release) and my action webcomic(ongoing, monthly release with one or two chapter buffer, please dont follow my example because i am extremely slow compared to others lol). I have additional projects on top of these but without the demand of a release schedule
I think being realistic about your speed and energy levels per project is important too. If one is a more complicated style with a bunch of action panels, then you obviously need to allocate realistic goals and release schedules for that vs a cartoony sunday comic strip style work thats easier to produce, or if you're doing something as simple as writing a novel vs drawing a comic
Unless you're contractually obligated to produce one or both works, just let yourself create and have fun with no obligations. if you find you're able to work on both projects at a pace you're comfortable with, then kudos to you and I hope you have success with both of them! do not let the pressure of "making it big" or becoming professional(unless that is your intention, in which case you should listen to professionals aka not me lol) keep you from telling the stories you want to tell