I would suggest that you try to limit the current to about the rated current of the motor. If you go higher, you will saturate the magnetic circuit which won't do you any good.
How about at big resistor in series with the diode? The current will still rise quite quickly. The motor resistance won't be significant, and with no inductance, I would go for somewhere around 30
hm: to limit the current to about 8A. Without a resistor, the maximum current could be very large and difficult to measure or estimate.
At 8 A the motor will last for half a minute or more. You will get about 2kW of heat generated in the resistor, but wirewound resistors are very robust and have huge short-term overload capability. Depending on how many stops per hour, I would guess that a 100W resistor would be fine.
I have used some 25W resistors where the power peaked at about 20kW for about 5ms, and they don't give any trouble.
The diode will be quite cheap, so it is a good idea to aim for a big overrate, and go for somewhere around 600V and 25A. Diodes are much less tolerant of overload than the resistors.