Large data sets cause SoapUI NG Pro to choke/freeze/crash

I am dealing with testing a service that is rather large. In my shop we do postive testing (good data, good scenarios), negative testing (bad data, bad scenarios), and null testing (missing data or empty string). I've had no issues up until recently when testing two new services that we have in development. I am trying to build SoapUI testing projects for them and I am running in to issues. I am relatively new to testing (I have a background/degree in software development) and to SoapUI (I've been on the current job for just under a year) so I need help.

The project in question has methods to add data, delete data, and update data. I've only touched the surface so far and am still trying to accurately and fully test the add method.

In the default add method, we have roughly 250+ different pieces of data. My method is as follows:

• Generate data to satisfy the Add method and any permutations there of (based on choice elements, etc)
• Figure out, based on wsdl/schema constraints, what NULL tests will actually work. Because some elements only have a max length value and no minimum length, using <element></element> is a valid test. The other type of NULL testing is to not even include the element. 
• Generate data to uniquely test every permutation of a NULL test that will work (we have a middleman that'll deflect any schema-invalid request, so I don't have to generate data for those.) 

Based on the steps above, I have roughly 230 NULL test cases that are schema compliant and should bypass any schema-validity checks. Right now, in a properties step, I have 58800 pieces of data to satisfy every possible test case that's expected to pass and add data in our service.

This is, obviously, a LOT of data. I'm running SoapUI NG Pro, and it's absolutely choking on this much data being stored in the project. My Project itself is roughly 50MB in size. The properties alone take up nearly 6MB of space. 

Am I doing something wrong? Is there a better way to do this? Any and all help is MUCH appreciated.

Some of my constraints are that any steps I take to test a service have to be easily reproducable and repeatable as we deliver these SoapUI projects to partners so they can use them to test our services. Please, though, give me any and all idas you have. I appreciate it and want to say thanks in advance.