Latency using external hardware reverb

Working with Cubase 8 / Lynx Aurora 16 setup.
Using 2 hardware Lexicon PCM 70’s (one for the drums and the other for the vocal) as external reverb.

Phase: Recording is finished. Time to mix.

While listening/playbackI have bigger buffer size.
Using hardware Lexicon’s to monitor various presets through 2 stereo buss channels - in monitor mode. Making user presets…

Preparing for mix I decrease buffer size, and print/record those reverb returns to 4 new channels (no problem)

Starting to mix I increase to bigger buffer size.

When listening (playback) - there is latency in printed reverb tracks. They do not have the same timing as they had when I was only monitoring through them.

Question; How do I figure out what is the latency of printed/recorded (hardware reverb) tracks - during playback, in order to be able to shift them back ?

I remind that it is reverb that we are talking about, so some pre-delay, minimum reverb time and various other effects (small chorusing) are part of all register and user presets in presets that I use.
Do I have to record some short/sharp click signal through external hardware Lexicons (print them to new tracks) and then check ?

Thank You:)