Skin Input

Hi all , I need some input for my skin. I am going to cover the top with 1/8 " hardboard ,then put FRP on top of that with adhesive. I have my spars 12" apart , they are 1 1/2" x 3/4" poplar . My question is should I glue the hardboard to all the spars & side tops ,then screw it down ? Or would screws every 4 " to 6 " be enough without the glue? I am wandering if the screws could possibly come loose later .
Am I worrying about nothing here or what ?
Thanks in advance for all the suport. 


