My double-sided projects are usually a glue-up where I trim the edges afterwards, which makes the material a fraction off from how I set it in Aspire. Or sometimes I'll just grab a piece of material setting there, but again is different than the setup. True what everybody said about the pegs and corner datum position is actuate, however, if the material size is different the corner datum position would need to be re-positioned.
When I say I do a jig, it's simply taking some scrap wood and either screwing or shooting it with brads to the spoilboard and either screwing the material to the spoilboard or to the jig. It takes seconds, which is a whole lot faster then doing the pegs. And if I forget to reset the datum (which I was my habit when using pegs) it won't be misaligned if I use the center.
Maybe if I had more patience and my memory wasn't only a few seconds long, I would do it the other way, but I like EASY.