Planning to make this jig.

It calls for wood that is 5 inches in width, but the 1x6s I bought are 5 1/2 inches in width. Question is whether I should cut off that extra 1/2 inch, which will be a pain for me to do since I don't own a table saw. Would need to do so with a circular saw.

Is the 5 inch size necessary for shallow frames? Medium frames?