My tips:
1. Basically the same as what Emz said but I don't export any tracks - in Pro Tools, setup a click track, you're going to do this anyway, then send it to a new track. Record a few seconds. The output sound be on the grid if its not then you've got a problem. I then copy a few clicks to each track that's going top go the outboard gear that's got latency. If it's all analogue you should be okay. I use spdif to my Kemper and there's a small delay.
2. If your DAW has hardware delay compensation: Record the above mentioned click through the outboard device and workout what the delay is. You can then add this to to you I/O setting if you're DAW has it. This is the best because you never have to adjust your tracks. I also workout the delay in samples then convert it to milliseconds, I've found this to be more accurate than trying do it in milliseconds because a sample is the smallest selectable part in your DAW and often the delay is not to the exact millisecond.
For example, I recently calculated the delay of an outboard processor to be 9ms because Pro Tools would only allow me to select whole milliseconds. After switching to samples it turns out that the delay was in fact 9.2ms. I put this into the hardware delay compensation settings in the Pro Tools i/o for that send and the result was sample perfect delay compensation.
Sample rate/1000 = samples per millisecond so at 44.1k sample rate 1ms = 44.1 samples. If you workout your delay is 406 samples just divide that by 44.1 and you'll get the result in milliseconds, in this case 9.2
3. If you have a Kemper amp make sure you turn on the "Constant Latency" setting found in the "Master" output settings. Without this on you will probably end up crying.
