I actually really like my FSA mini-TT bars with bar end shifters, but I find them a tad too short. I have the bar end shifters halfway in which extends them a little bit. I want to get the FSA clip ons and then cut them off befor the rise section. If I want about a 21cm extension which length bars do I buy? (assuming it is possible to cut them down and put the shifters into the ends).