It will look nice...I promise.

I was just reading an article that talked about pull sizes and it says to use 1/3 or 2/3 the width of the door/drawer (larger ones are en vogue right now, so it's personal preference.)

Many people , though, don't care for the longer ones because of a possible snag-factor...

Whatever you choose, make sure it's comfortable to grab (not so shallow that they're only "fingertip" depth...)

I agree, functionality is the first requirement. Pick something simple and classic that will stand the test of time. There's nothing wrong with having knobs and pulls both, almost every kitchen has that. Just make sure they're visually compatible.

Many interior decorators like the use of knobs for the cabinet doors and pulls for the drawers. After considering all of my options, I decided to go the same size pull for all the doors and drawers. To my way of seeing it, that just made the kitchen more cohesive.

Once I made the decision to go with all pulls, I did consider different sizes for different sized doors and drawer. However, I did not like the appearance at all. So just went with one size for all. It is very important to use pulls with smooth edges to prevent snagging. For example look for the first type, not the second type shown below. These are just my guidelines for your consideration.

I have been attempting to get the pictures to post at a decent size and they will not - they are gigantic. But look at the European style (the ones that can snag) and the cabinet handles (which for the most part are smooth ended - but there is one that is more in the European style) at this link.

Pulls for Cabinet Doors and Drawers

If I went 1/3 of the drawer size using my biggest drawer as reference would it look okay for my small drawers? If I used the same size as the big ones? My biggest drawer size is 30" and my smallest is 12", would that look ridiculous using the same size all around?

That would be a 10" pull for a 12"drawer...

As long as they are all the same style, use the size appropriate for the door or drawer.

@Walnut, the cabinets haven't been installed yet and I'm hoping to have the hardware so the cabinet company can install them rather than my contractor which will cost me more money

Cindy, while there seems to be many formulas and opinions re: knobs and pulls, I decided to go with all pulls in my new kitchen. I'm very glad that I did. It looks very cohesive and calming to my eye. I also decided to go with just 3 lengths for the pulls- basically small, medium, and large and that worked out well too. Even though it might cost more $, I would really reconsider and wait to have the hardware installed until your cabinets are in. It makes a BIG difference to see them in the space and be able to play around with various sizes and shapes. Good luck.