Use the benefits of scale to your advantage. 24v cells are mass produced because it's the type of panel used on homes. So they are cheaper per watt and often found really cheap used. The higher voltage gives you less amps (ohms law) for the watt produced, so wire size, component size and general issues go down.
12V panels are for the hobbyist or small application, like an RV. So they are more expensive and cause wiring issues on a larger scale.
Frankly, I call anything under 150 watt (or 12v) not worth the glass. I have a stack of about 25 of them, and they are just not worth the hassle or cost. If I need 12V for something, I will use a 250 watt, 24v panel and a MPPT controller to step it down to 12V. Or better yet, use a 24V battery bank and use a DC-DC converter to drop that down to 12V.