Sure - I might add, I also have some basic volume levels set for each kit piece, and I have it all set to start right at the beginning of the whole signal chain - meaning setting individual Battery 3 Kit volumes for each cell, as well as the overall Master volume for Battery 3.
Please note that the following is simply what I do for ME, and that others will quite likely do things differently - it's just the way I evolved into thinking, and I am happy with the results.
So, when I create a custom kit in Battery 3, for use in Sonar projects, I will load the desired kit, and will set the Output Channel for each cell of the kit to go to a separate stereo output channel (32 available in Battery 3), and I set the master volume for Battery 3 to -8 DB.
I then go to Sonar, and set up a Drums track folder, and add a midi track to the folder, and a stereo audio track for each kit piece that will be coming from the custom Battery 3 kit. I also set up whatever sub-buses I will be using, which will be: Drums Master, Parallel Compression, Toms Bus, Cymbals Bus, etc....), and I will set each audio track's output to go to the correct sub-bus. The audio tracks will have their Inputs set to the correct Output Channel from Battery 3 for the corresponding kit piece.
Then, I create a simple quick level-testing Step Sequencer midi clip, where there is a drum beat for each of the kit pieces. Sonar will set Step Sequencer clips initial velocity to a uniform value of 100, so with this midi clip, I can play it over and over as needed to get all of my kit piece volumes to be at -18 dBs.
To do this, I play the midi clip, and that will create peak volumes I can see on either the console view or on the track view, for each track/channel. That gives me some sort of initial volume for each kit piece. I then figure out the difference between each of those volumes and my target volume of -18 dBs, and I go into Battery and use those volume difference calculations to adjust each cell's output volume to whatever is needed so that when I again play the midi clip, I can see all of the kit piece volumes are as close to -18 dBs as possible. (this will take a few times playing the midi clip, but it is very short. just having a single 'hit' for each kit piece, so it only takes a moment to play it).
Throughout the above process, I do NOT use any audio track's Input Trim, nor do I move any Sonar fader for any of the drum audio tracks off of Unity. I want to have all of my drum kit's initial volumes controlled by a combination of separate audio output volumes for each kit piece in Battery 3 and the Battery 3 master volume. (I save the custom kit in Battery 3, as well, named for whatever starting kit I am using, including all the samples)
When it is all set, I do a select all to export all the drum audio tracks, as well as their Drums track folder, and the Battery 3 instance, as well as all of the buses and the routing assignments, and this will become a new Track Template for this particular kit - as I save it as a user track template.
(once you create one new drum kit track template, you can load up a new project from one of your existing templates, and load up a new kit and make the needed adjustments. This will save you a bunch of time, because you will have the Drums track folder, all of the audio tracks for the kit pieces, a midi track for drums midi data, all of the sub-buses you create, and all the routing assignments for the kit piece audio tracks to whichever sub-bus is appropriate. That's a great starting point)
I hope the above helps, and makes sense. I can try to answer any questions you have. There may be easier or better ways of doing all of this, but I like how the above works for me, as I get really good volume settings really quickly, by inserting drum track templates as needed into new projects. For ME, this saves a ton of time.
Bob Bone