Kathi,
I went with the 1 1/2" one, nice pictures! I wrapped the cut off screws with electrical tape so they would be secure in the holes. Good luck with the project.
Ozz
'07 3400RL 2nd RTU
2 Golf Cart batteries 3,000 watt inverter, automatic transfer switch
Honda 2000 Generator, Maytag's with 220 Dryer
Stationary domed Sat. dish, LCD 12 Volt Amp gauge, LCD Tank Monitor
3 added 120 volt outlets, On Board Air; 12 Volt Viair 450C compressor
2006 Ford PSD 4x4 Off Road Lariat, Hadley Air Horns, Truck inverter with 110 volts: laptop, Color Backup Camera, Awning lock