Mark - why not just digitize the audio at 33 1/3 and then resample in your audio editor of choice?
Some really bad vinyl I used to take in to an engineer buddy with an infinitely variable turntable, throw on a known length cut (like a :30 radio leader)... figure out how long it took to play (if it was, say, 90 seconds, you'd know you were playing a 33 at 11.1rpm) and then resample at 1/3.
That way pops, clicks and all manner of ugliness are minimized - a click lasts a certain length of time and it at a certain frequency no matter how fast it's played... if you play the disc slower, by the time it's resampled - it's shorter and higher in pitch, making it less noticeable.
Just my two cents.
Remember to use the right stylus for the composition of the records, too, especially if they're shellac or aluminum blanks.
Bren R.
