Three Column Field Group - Customization

I am using a Custom 3 Column Field group for this element in my form. I would like the TYPE to be a 50% and Start Date / Duration to both be at 25%. I have tried editing the HTML in my landing page within the form, and it constantly reverts back. I can't find in the Eloqua form editor where I can tell it to make the TYPE the largest of the three columns. I have made Start Date/Duration both SMALL in the field size and TYPE is Large trying to force it to flip.

Any help is appreciated!