Ok, so last night I wanted to try some of these great suggestions here on TM. I've got a King Silver Flair (1991) and an Asymmetric 3C+544 mpc. first I tried the tape around the mpc to change the leadpipe length and make the horn slot better. But it got worse -- I had mid range slotting problems (F-High C). I tried several different lengths in increments of about 1/4" (bout 6 mm for you metric people)- to extend the length to about 3/4" ( to about 19mm). NONE seemed to help. Then I tried putting dimes in the bottom caps of the valves (The King Silver Flair is already heavy enough) - 1 dime each in the valve caps -- then 2 dimes in each -- so for 60 cents -- I couldn't find any improvement in slotting or sound (in my opinion). Lastly -- I "unpimped" the horn -- recalling that rowuk mentioned that "pimping the horn" didn't make up for actual practice -- then I practiced on what is apparently the "BEST" setup for my horn. The manufactured horn "as is" with an Asymmetric mpc "as is". maybe I should put a pencil in my mouth -- but I can't get ANY slotting with that method, and virtually NO sound. LOL, lol, for all the Horn Pimpers out there -- I'm glad it works for you.