You need to go down to t4. Alternately, the lamps could be placed on the diagonal.

Thanks, David. I asked my GC if we could place them at an angle, and he thought the pattern of light produced would look weird compared to the straight runs on our larger banks of cabinets. I'm not sure if he is right.

I will look at T4s. All 4 banks of cabinets are wired together. Could we stick with the specified Lithonia Z Strip T5HO fixtures on the 2 larger cabinets and use T4s on the 2 smaller cabinets and control them from a single dimmer, or would the 2 types be incompatible?

Here is a link that might be useful: Lithonia Z Strip

It may not. If dimming capability is required, you need dimmable ballasts which in turn could push the cost above LED.