I do not rely on just prying the grills from their outer edges.
Get some wire, thin rope, etc that you can thread under several of the grill slats, spreading out the load and minimizing any breakage. Keep your pulling force at the edges of the slats, not the center. Pulling on just one - not good.
Using the rope and side prying - putty knife - you should be able to slowly work the 8? prongs loose. Keep re-threading the wire/rope so it is close to each prong, and use an incremental approach, much like tightening head bolts, etc. Once each of the prongs is loose, the process gets pretty easy.
Be sure to cover the cowl paint with tape, thin wood, etc where you use the putty knife to avoid paint damage.
First time removal is, obviously, the most difficult.
This task is much like removal of the rear, gill windows. Seems more difficult beforehand, and falls into the "That wasn't too tough" category once completed.
I think you, YES, EVEN YOU, can pull this off.
Larry