Re: 164 TS hesitating during acceleration
I have just checked the afm resistance readings on my 164. My readings are substantially the same as yours, ie 370 closed rising steadily but rapidly to 1070, holding around 700 to 800 before falling back to 600 fully open.
My guess is that your afm is OK.
The "gunged up" separator is not uncommon it results as you found in deposits on the intake after the afm, it often causes irregular running at low throttle due to deposits around the throttle butterfly. You should check the small drain pipe from the bottom of the separator to the crankcase, it blocks where it enters the crankcase and results in the separated oil passing to the intake. Just disconnect it at the separator and blow through it to check it is clear.
I have just looked at your nice thumbnail pic. It occurs to me that the distributor shown is wrongly positioned. The outlet for the HT leads should be approximately horizontal and not pointing upwards. This has no effect on the timing, but it does mean that the spark is jumping a gap from the rotor arm to the HT contact, which results in burning of the contact.