Well done, that is my plan to make something like that cabinet. 

I currently have 2 types of trays like shown. One is premade with 1/2 and 1/4" shank spots, and those little plastic collars. The other is also both sizes, just holes popped in a piece of black foam. When I had more of a cabinet for my router they seemed to be ok. Now I have an open storage area under the router, and there isn't a good space to keep the forms, so they are always getting in the way.