Impossble to tell without a picture, but I can tell you I'd never use any form of wood that's showing to do this job.
What we do is is a meter mounting siding block and run the siding around it. Before installing it we put a piece of 3/4 Advantec subflooring just sitting inside the block.That was the screws have something to pull on.
Mount Blocks and Utility Vents
The box stores most likly will not have these, but any real siding supply company will.
By doing it that way the reel gets attached directly to the side of the house but there's 0 chance of water getting in behind the wall.