Wow, 1/250th, that is impressive. Who would of thought. I remember always looking for something to set it on then hold it down firmly, before snapping. Really great idea you had.
About 1/250th of a second. Unmodified it originally measured 1/40th of a second. The unavoidable clunk associated with tripping the shutter was leaving me with too many blurred negatives.
(there was a url link here which no longer exists) made by me on 5/21/2008 describes in more detail the modifications I made.