The CW mode of the Tempo is much easier to use than to understand.
The Tempo One CW mode requires the use of the Clarifier. This is why the Clarifier control has CW1 and CW2 written on the front panel but unfortunately they are not mentioned at all in the operating manual. There is no explanation for how those positions are used. The Clarifier markings indicate about 1 kHz steps.
Below is a photo of the Tempo One front panel band switch and Clarifier. Bands with white numbers use a 9001.5 kHz carrier crystal. Ones in red use the 8998.5 kHz carrier crystal.

Below is a diagram of how the the Tempo One works in CW mode on 20 M.

On receive, the incoming 14 MHz signal mixes directly with the VFO at 5 MHz to create a 9 MHz IF signal. The IF signal mixes with the 8998.5 kHz crystal oscillator to produce an audio output at 1.5 kHz.
The transmit frequency will not be 14 MHz however. The leakage of the 8998.5 kHz carrier oscillator past the 9 MHz SSB filter is used to mix against the first LO to create the transmit signal. If the VFO remains at 5 MHz during transmit, then 5000 + 8998.5 kHz = 13998.5 kHz. The transmit signal will be 1.5 kHz below the received signal.
To remove this offset, turn on the Clarifier; set to the CW2 position on 40 and 20M. Tune using only the VFO until the desired CW signal tone sounds like 1.5 kHz. This can be compared to the pitch of the Tempo One side tone which is set to 1.5 kHz. The Tempo One will now transmit at the same frequency as the received CW signal. Do not use the VFO to tune further. The above procedure corrects the VFO so that the transmit frequency matches the incoming signal frequency. Use the Clarifier to adjust for a comfortable listening tone after the VFO position has been set.
The explanation of why this works is as follows. The use of the Clarifier set to position CW2 lowers the VFO frequency by 1.5 kHz. To compensate the VFO must be tuned to 5001.5 kHz to eliminate the offset created by the Clarifier so the LO frequency is once again 5 MHz during receive.
When the Tempo One goes to transmit mode, the Clarifier offset is eliminated so the rig transmits on 5001.5 kHz + 8998.5 kHz = 14 MHz, the same frequency as the incoming received signal. The use of the CW2 position is simply to cause the VFO to be tuned to 5001.5 kHz. Once that is done, the VFO is not tuned again since it is at the correct frequency needed for transmit. The Clarifier can now be adjusted for a comfortable listening tone since it only works during receive.
There is a potential complication on the bands that use the 9001.5 kHz carrier crystal. The rejection of the carrier by the SSB filter is greater for the 9001.5 kHz carrier than for the 8998.5 kHz carrier. To get around that, the Tempo One uses a varactor to tune the 9001.5 kHz carrier oscillator 200 Hz lower in frequency to 9001.3 kHz. This provides more carrier leakage for the 9001.5 kHz crystal which is desirable in this case.
Tuning a CW signal on the 80, 15, and 10 M bands is similar to 40 and 20 M except the Clarifier is set to CW1 which creates an offset of about +1.3 kHz. Tune for a 1.5 kHz tone with the VFO as before on 40 and 20 M. This will place the VFO at 5.4987 kHz to cancel the Clarifier’s +1.3 kHz contribution as shown in the figure below. Once the VFO position is set, the Clarifier may be adjusted for a comfortable listening tone as before.

Although the CW1 position may appear on the front panel to be a 1.5 kHz offset it is not due to the actual characteristic tuning curve of the Clarifier shown below. The Clarifier turned counter clockwise from the “zero” position compresses so that CW1 which looks like 1.5 kHz is closer to 1.3 kHz.
I should point out that the Clarifier has two sets of markings, one in white in one in red depending upon the output band. The graph below is data taken at the VFO using the white markings as a reference.
The Clarifier on this Tempo One had an actual CW1 offset of +1.388 kHz and a CW2 offset of -1.975 kHz.

The Tempo One Clarifier has no gain calibration adjustment only an adjustment to set the “0” to the same frequency as when the Clarifier is off. To add a calibration adjustment a 500 k cermet trimpot was soldered across the end terminals of VR7 which is the Clarifier potentiometer. The cermet trimmer was then adjusted so that CW2 gave a +1.5 kHz offset. The measured CW1 offset was 1.312 kHz as shown below.

The photo below shows the actual shift of the 9001.5 kHz carrier is about 182 Hz.

Below is a test of how close I was able to zero beat the incoming signal using the method described above. The signal in the center is from an Icom 705. This was on 15M. The Clarifier was set to CW1, then the VFO tuned so the received tone from the 705 matched the Tempo’s 1500 Hz side tone. The lower signal to the left of center about 35 Hz away from the 705 signal is the Tempo One transmit carrier in CW mode.

To tune a CW signal on 80, 15, and 10 M, set the Clarifier to CW1, tune the VFO for a 1500 Hz tone matching the Tempo One side tone. This zero beats the incoming received carrier with the Tempo One transmit carrier. Use only the Clarifier to obtain a comfortable listening tone after zero beating.
The same procedure on 80 and 40 M but use CW2.