Is there really double the feta than tomatoes?

Crumbled feta is an inferior product, made domestically from cow's milk rather than authentic imported Greek feta which is made from sheep's milk.

Almost all crumbled feta also includes an anticaking agent like cellulose or potato starch.

https://www.americastestkitchen.com/taste_tests/1860-crumbled-feta

As mentioned by AJ, you are free to change the proportions yourself, this preparation is very forgiving. Personally I would just go by my own taste buds.

I would also go with genuine feta cheese imported from Greece especially because the feta flavor is the one of the two dominant components.

Best of luck.

Sun-dried tomatoes have a strong, almost concentrated flavor, so it would make sense that you would not need as much tomato as feta. I'd go with the recipe as written - and if you think you'd like more tomato, then add some. This seems like quite a forgiving recipe, in terms of quantities and their ratio.

As for using crumbled feta, I'd say that yes, you certainly could use it. Crumbled feta tends not to be as flavorful, or briny tasting, as that which is sold in brine, so be sure to check for salt, adding more if you think it's necessary. You might want to a add a touch more white wine or red wine vinegar, too, to brighten it up. ;o)