personally, i think a 30" would be too small. With how your space is and the size of your table, hands down i'd do the 42". Though the room isnt massive, it isnt tiny either and this will make it look more purposeful. I know the images below arent exact but will give you an idea of the difference. The first is what a 30" over a 60" usually looks similar to. the other is larger. Especially with the glass behind it, I think it would be beautiful in 42"

Always better to be too big than too small, so go 42”

The rule of thumb is that the light fixture should be 1/2 to 2/3 the size of your table. So, 30 - 40 inches. I'd go with the 42 inch.

Make a statement! Your house calls for the larger one, the small one will get lost. I have a statement chandelier above my dining room right after the entry, it really makes the space.

Be bold and make a statement!