I would think a bigger tank is better anytime. Even if you don't need the range, don't mind to fill up (because it is on the way / a nice break of a commute) etc. It is just nice to have the range if you need it.

I fuel up once a week now (tank doesn't drop below half usually) as we are experiencing fuel shortages and my tank is dirty. Normally I would run a tank till the end as I don't like filling up. MY 2010 5.0 SC Galway green and sand interior!!
Have the Faultmate MSV2 Extreme to be tinkering with the settings etc. !!