To avoid the 'TRIG' input from affecting the sequence, I made changes. This schematic features less IC count, by taking both types of counts, in one CD4017 IC.
First, notice the 'state 0' output is unused, as you need to time at least one (clock) count. Next, see the first f/f stays set, usual dual multi-vibrator circuit will also have some way of avoiding a re-trigger, until cycles complete.
Meanwhile, arrival at a first-count sets the output f/f, and a second-count times that (output pulse).
For example, you can set 3 clocks as first timer, that's 500 nSec. (6 MHz clock rate, from video sys).
Then, a second rotary switch, sets T2=3 clocks, also, for a 500 nSec output pulse (followed by all clear state.)
Of course, a 'bug' there, as the rotary settings should be overlapped. Plus, not ideal as rotary mis-settings are possible. Some 'glitches' might literally only cause a slight flicker, as this is for a screen curser timing...