You should be good with setting the output of the regulator to anywhere between 12.6 and 13.4 volts. I do the same thing with my battery box which has two synchronous regulators. One is set at 12.8 volts and the other is set at 13.2 volts.
The only consideration is whether you will be using any "12v" computer accessories powered by your battery. Those most often have specs of 12v +/- 5% or 10%. That means a maximum of 12.6 or maybe 13.4 volts. You can run them at the top of the range or a little more but their lifespan can be reduced quite a bit due to internal heat build-up. (These computer devices often use 5 volts internally and dropping the input voltage with their internal regular generates heat. The higher the input voltage, the more heat they generate internally in normal use.) This usually applies to USB Hubs (non-industrial) or power for USB Hard drives or SSDs and such.
All astronomy equipment is usually good to at least 14 volts although there are a few exceptions. Some astronomy equipment is rated up to 15 or 16 volts. In general, your cameras, mounts, and so forth will be quite safe at anything up to 13.8 volts. (My battery box outputs 13.5 - 12.5 volts unregulated directly from the LiFePO4 battery, 13.2 volts regulated, and 12.8 volts regulated.)
Edited by jdupton, 27 October 2020 - 02:02 PM.