This
http://annebonnyslocker.com.au/ckp/p...rank_motor.htm says "bolt hole must be 4" / 10cm directly below the centre of the drive shaft." I have a 206k here and the hole isn't offset, so it must be distance from the center of the shaft that is the problem. Measured it w/o taking the motor or hand wheel off, and it's in the 3.5" ballpark. But a new hole could possibly be machined 1/2" lower. Looks like there is enough room there to do that, but I am not a machinist.
Isn't there a smaller size hand crank, like 3/4 size, for the 99k and 3/4 size shuttle machines? But that would have to be an original Singer crank, not a reproduction. The reproductions are all full size, as I recall.