...
Disk-gap-band parachutes where designed in the 1960s for rockets about the size of Hermes which attained comparable attitudes. The majority of modern application have been at low dynamic pressure on interplanetary probes (Viking, Huygens, MSL, etc). Although conical ribbon parachutes have a better design linage and are slightly more stable, they are considerably more difficult to manufacture. The rocket will only fly with a conical ribbon if later analysis shows that deployment dynamic pressure will be high or deployment will be chaotic.
Current Analysis
I ran 15 sims of the rocket pre-new motor at various launch angles and masses. The above figure shows conditions at apogee +/- 10 seconds. From this, one can calculate deployment forces and see that the deployment dynamic pressure will likely be less that the steady-state descent dynamic pressure.
write me