Christmas Fabric Postcards

I made a few fabric Christmas postcards to send out this year - a little gift and greeting all in one.  There is just enough room to write a short message and address.  I like to make them simple with everything stitched down securely because they travel in the mail better that way.  I have mailed fabric postcards in the past with just a first class stamp.  However, I have had clerks charge the extra 'non machinable' postage which is currently 17 cents.  So, I plan to put two stamps on these to make sure I'm covered.  Since I am going to request a hand cancel, it helps to have the extra postage affixed, and to also mail them early before the Post Office is swamped.