I Need Glue Advise - Dow Styrofoam R4

I’m going to make a stringerless board out of Dow Chemical’s R4 residental insolation. It is the blue stuff that comes in 4’x8’ panels from home depot. They only had 3/4" panels, so I’m going to glue up 4 - 24" W x 8’ L sections to net a 3" thick section. I’m going to bend my rocker into it when I glue it up. I read the Eric J. account of using elmers glue (that had some good info, thanks Eric), but I don’t think that is the best way to go. Does anybody have any experience with this? I was thinking of using epoxy glue (you know the kind you can get in a big syringe which has two chambers, hardner and resin 1:1, mix it together and it kicks), but I don’t think it will spread very well. I heard about panel adhesive, but I’ve never used it. Or what about liquid nails, would that melt my foam? I’m trying to find something that will hold my rocker once my weights are released, but something that won’t be so hard and brittle that it will cause problems when shaping. Thanks for any info.