The following modification to B will also add some dead-time to prevent glithes on the output, because of the possible "race problem" when switching. Yet another way (without the diode-cap-res) is to create a delay with inserting a buffer (2 x 4093's in series) in one leg as shown.
If all this sounds too much for you :shock: , simply take a SG3525 and apply a DC control voltage directly to the compensation pin (or to pin 3 on a TL494 for that matter) to adjust the duty cycle manually. Sorry, I always like to show how things can be done discretely so that newbies can also learn in the process.