Inside screws

I use a set that uses a common handle and has various bits including square, hex, straight, and cross. These bits also fit a magnetic bit holder for my power drill/driver. It seemed to me to be a better solution than hunting for a single-purpose driver.

I hope that works for you but if you find that it isn't working quite right you may have to move up to a Robertson #2 - which is the common size, or at least it is in Canada.  Typically the #1's are slightly smaller and are used for electrical stuff and smaller screws.  There is also a Robertson #3 which is more of a speciality head and is used for things like connecting power cord to the back of appliances like dryers.