Stryped wrote:
"If the plan calls for 1/2 inch and I go with a larger diameter, say one
inch, would the spacing between the elements still be the same?"

Maybe not, if impedance of the line segment is important. See a chart
like Fig 19 on page 24-15 of the 19th edition of the "ARRL Antenna
Book". This shows "Characteristic impedance as a function of conductor
spacing and size for parallel conductor lines."

Best regards, Richard Harrison, KB5WZI