Recently I had some of these done Lee's Machine shop. These are not conventional venturis but rather the type that fit down inside the case. They were absolutely perfect! They are hard to come by and really about the only chance you have of getting these is to have someone that knows what they are doing make them. I highly recomend Lees Machine shop if you need something like these made for you.
Your not saying which venturis you had made. Randy Smith has factory venturis for most all of the Enya lineup. Now if he made them for the square venturis found on the 5224 that would really be something.