The only two solutions that come to mind, are to build your own, or build an interface to use the 10K CK model and adjust the signals to suit the 250EX. I believe it's just using the 47K as a 0-5 voltage divider, so the 10K model might work ok out of the box. Might not be 100% linear in the control, but could work good enough. If not, there are a few easy and not so easy ways to make some adjustments to suit. Everything from just adding some trimming resistors, to a full blown microcontroller solution.
And another option is to chop up your pedal and make it into something that you can use. In confined spaces I've used a pedal under an arm, or even leaned my head on it under a semi trailer. While not ideal, it could get the job done.
I scratch built my current finger controller and have been pretty happy with it. Should be a post on it somewhere around here.
One thing I forgot, is the with longer up and downslope settings you can pulse the standard torch switch and get pretty fine amperage control by going into and out of the slopes. A lot depends on the kind of jobs you are doing.
Last edited by Rambozo; 03-07-2015 at 06:02 AM.
Long arc, short arc, heliarc and in-the-dark!