OK, I have four 150 watt panels and they are 32”x64” each. These are home system take offs. They make some 150 watts that are slightly smaller but not much.
Now let me share about these home take offs. If you are patient and keep an eye on Craig’s list they give these things away to get them out of their garage.
They age and then solar companies sell them new panels for their home systems. These home take offs are absolutely still GREAT for 12v or 24v systems!
So they would fit on the 10X8 foot roof of cabin.