Two questions to ask in these situations are: what is worst case? Which is not informative by itself, so we ask: for what duration?
Through much reading of data provided by Sure Bros. and others, at 1,000Hz the absolute limit in vinyl cutting is 35 cm/s. Reading further, the max found through measuring of many records was ~ 28-30 cm/s, at some place on two records (of many samples). Aside those two, the highest were ~ 12 and 15 cm/s. For a cart output measuring.0005 V (.5 mV) @ 5 cm/s-1,000 Hz, 30 cm/s is 6x and 15 cm/s is 3x above test spec. From an article I dug out from Stereo Review printed in 1968, the writer said that few records have anything much above 15 cm/s. So I have taken for myself that 4x the test record spec is the R/L actual worst case that we should have any concern about.
With a cart of .5mV going into a 20x SUT and a 125x (42 dB) phono pre, that comes to 5V. Worst case.
The second question is duration of the event. Look at the data on this page:
https://www.dpamicrophones.com/mic-university/acoustical-characteristics-of-musi...The attack duration of snare drum measured 5-8ms, bass drum:8-12 ms, tympani (all sizes): 10-18 ms, trumpet: 20-40 ms. These are the loudest instruments in the orchestra. 20 ms is 1/50 of a second. That would be nigh impossible to attract perceptual notice, for one, and I don't think it would trouble even a SS preamp input stage overly much. I don't know for certain, but I don't think even 50 ms (1/20th second) would cause too much trouble, but who knows.
So then with your cart and SUT, we have "an extraordinary vinyl event" resulting in 5 volts output of a 42dB phomo preamp for 5-40 milliseconds.
After all that, your own experience is the final determinant. If you notice distortion when you set the phono preamp higher than 40 dB, then there it lies. But that might or might not occur with another phono pre, SS or tube.
I don't think you need to stress much over it because it might be fine with the ZP3 as is, and if not you have the option of replacing the 12AX7 tubes with the 5751 set.