Fireplace sizes began to evolve in the 1930's to wider openings while often retaining a shallow depth, often resulting in a fireplace 30" to 36" wide yet only 12" to 14" deep.  Most gas logs require at least 15" depth, so this creates a challenge when the homeowner wants an open gas fire. A gas coal basket that fits the depth may seem small since they are generally 22" wide or less.

Try visually filling the fireplace opening by adding andirons on each side.