Acoustic soundboards serve a totally different function. The top should be thick enough to limit feedback issues when played at volume. Chris mentioned he was successful at 3/16" using Spruce worked well with his design. The design should be considered when choosing this thickness. Depending on how much material is remaining under the top(supporting it), and type of top wood. You may want a bit more or less thickness.
Peace,Rich
He implied strength of the top, hence if 1/8th will hold the guitar together, 3/16th will be fine.