Okay ... after getting some well-needed experienced advice, I have come to something that will make everyone happy, and I will feel comfortable with.
Neo suggested I get Owens Foamular from Home Depot, which is covered in a plastic film, therefore making it impossible for the foam to eat away at the acrylic. Thanks Neo!
I don't know what everyone else is using, but this will work for my application. If this is what you were talking about, that's fine, but specific details are important
Now ... on to the build. Will be posting plans soon and buying materials soon as well, once design is confirmed.
Let me ask what part of the whole 3\4 plywood no foam part did everyone not understand? With weight on that foam the plastic cover will give and the acrylic will come into contact with the foam. Its simply chemistry people acrlic and patroleum dont mix well. Just for future reference plan out all materials and build a blueprint of what you want before you start. Having everything planned and taking PROFESSIONALS advice are probably the most inportant 2 things you can do with a new consturction venture, you havnt done either.