To get 200 psi at 9000 ft would require some pretty tight squish.There is no short cut for a well set up high altitude saw. Why you do not have have four or five saws for the correct altitude seems unusual. One or two saws for 9,000 feet and above with the rest for 7,000 feet and lower. Auto tine will not tune any saw properly as with respect to altitude. All they do is adjust the carburetor so the saw will live. A high altitude saw needs compression at or near 10:1 or maybe 200 PSI. Timing needs to be advanced at least five degrees. My saws almost perform the same at higher altitudes then at lower elevations. I would never other than a small start up session run a high altitude saw at 5 or 6,000 feet or lower. Thanks
I have some saws at 160 to 170 psi that do just fine.