Update: Apparently this is quite interesting to a number of people. I have rescanned the manual, properly compressed it and which you may find it here.
Found this manual at one of the older transmitter sites:
Entire manual is available for your reading pleasure here: Raytheon RL10 limiting amplifier
As this is an older design than either the Gates Sta level or the Collins 26U, it may not be as useful to tube audio enthusiasts.
The main issue with the Gates and Collins unit is the GE 6386 remote cutoff triode used, which were great tubes, but very difficult to come by these days. This design calls for a 1612 or 6L7, which is a pentagrid amplifier. Feedback is provided by the screen of the following stage, a 6SJ7GT. Anyway, perhaps it will give somebody some idea on how to make a good tube compressor limiter.