The problem with cranktimings with your crank size (12mm?) is that about 0.1mm shaving of the edge of the crankshaft is equal to 1 degree. Ofcourse you can remove something visable but there is a chance it will be too much.
That is why those pictures with positions does not tell a thing.... (athough I suspect the timing is very mild and has some room to enlarge)
The most simple thing to do is use a dremel and a caliper.
Take a caliper and measure the diameter of the crankshaft on the opening of the crankshaft. That is probably arround 9 to 10mm
Use a dremel to touch one edge at the opening so the diameter will be 0.05mm smaller. Do the same on the other edge so the total will be 0.1mm smaller.
In that way you have changed the opening and closing with both 1 degree, it should be noticeable.
Here a pic how to meassure
http://www.euronet.nl/users/tooms/ftp/meten_krukas.JPG