For me it would depend on the piecing. I would put it on my big board face down and work across it making sure all my seam allowances are ironed in the proper direction. I would mist any stubborn spots as I go. After all the allowances are ironed I would start ironing the front being careful to pick it up and move into the next section rather then sliding it. Sliding will cause the seam allowances to ride up. You might like to put a table beside you to hold the freshly ironed sections. Good luck!