Sure I can help out with some more information. Pro does not change these fields so all good there.
If you look at this file:
\the-events-calendar\views\modules\meta\map.php
Within that template you’ll see the tribe_get_embedded_map() function is used – you can actually specify dimensions by passing additional arguments, something like this: tribe_get_embedded_map( null, 600, 300 ) – which would create a map with a width of 600 pixels and a height of 300 pixels.
Then you might have to modify the css for this class on that template:
tribe-events-venue-map
That should get you close to what you are trying to do.
Thanks