I think everyone is different. I ordered plans for a pvc puppet stage from
www.puppets-etc.com. It is a little stiff for me to fold, but I also bought my pvc pieces from home depot instead of from them. Maybe their joints fit together better. We used a denim curtain, but next time I would like to make it in velvet or something more luxurious. As for dimensions, I think 6ft wide is a pretty good start. For the height I would measure your tallest performer on his/her knees or on a stool if you are using one. For the back curtain I would measure head to toe of your tallest person. I am above average height for a woman (5' 7") but my puppeteers are amazons! They have to spread their legs far apart if they are using a puppet behind the back curtain, and then they complain......! So for them I will be remodeling the next stage to amazon height. Hope this helps.