By the way, Rick, I've played around with several values of resistors where the two 220Ks are located. I ran out of 220K, so I took the opportunity to socket those spots and test it out. I can say for sure that any value between 150K and 275K will work in either or both of those positions. Waveform and min/max speed will change, of course, but several alternative values will work in a pinch.
Also, different op amps make a subtle, but noticeable, change in the LFO waveform shape.