If it puckers, the sandwich wasn't taught enough. I tape my backing down too and I make sure that it is not lose on the surface. Then I lay the batting down and make sure that it is patted out as taught as it will go. Lastly, I put down the top (which is well-pressed) and I pat it out too to where the entire batch is nice and smooth. Usually, I don't pin right away, but walk away - relax my shoulders and give the top another "pat down."
I pin baste no less than hand-width apart.
My last quilt had no puckers at all and I do SID in both directions.
BTW, as long as the puckers are small, they will almost disappear in the wash. (Some of my earlier quilts are blessed with a healthy dose of the little nips.)