I would suggest that if you decide to "shim" under the saddle you consider keeping the entire length of the saddle supported--else the downward pressure of the strings could crack the saddle in two--plus the saddle in order to transfer the string vibration to the bridge, and onto the top must have a good fit on the bottom-- It'll work ,just shimming one end of the saddle,but the tone/transmission from the string to the top will suffer. I would suggest that you use card stock--the material business cards are made of,for your shim stock.Rest the saddle on a business card,and with an exacto knife,scribe around the card stock,make several-- be careful--the exacto is sharp-You may need to use one or two to get the height you need on the #6 string end of the saddle. Once you have that height correct on the #6 string,it may be necessary to re-shape the top of the saddle towards the #1 end ( to make up for the higher end). Better yet,have a new saddle made with a higher #6 end.