materials. 1st, 1" mdf is very heavy (even light weight mdf, which they make) vs poplar is solid wood, light weight but will want to move more than mdf which is very stable. I think your design may dictate the best material for the job.
I'm planning on using either MDF or poplar, both 1" thick. The panels
will be 1"x12"x72", and there will be four (three joints total). Thanks so much for your help! :)