I think at this point in my life, and with a 1st gen, anything bigger than a 6x12 won't be needed, thought I won't deny the added size would be nice. I am going to be traveling cross country and wanted something that follows nicely and for only having two bikes, 6x12 will be fine. Plus, the 7x12 is over the price limit I set for myself.
I'm sure I'll upgrade eventually. Maybe.
I do have one question for you. With those tie down plates (I'm assuming from Harbor Freight), what did you use to fasten them in? Did you wood screw into the floor or drill through and use bolts with nuts on the underside?
*Advantech flooring. Just another reason I bought the H&H.