Hmmm, all I have to offer are my thoughts on this:
1), if the volume is radically different, adjust the output of the hardware. If you want to discuss hardware, discuss the exact hardware you have(in case others have experience with that same hardware).
2), Delay Compensation is not automatic with hardware inserts(there is a setup page in IO setup for entering the proper compensation time for your specific hardware)
3), re the null test, signals will never null in this scenario. Adding a piece of hardware in the chain will never null, and should not be expected to.
Don't get me wrong here, I love hardware as much as anybody! But I recognized the issues and limitations and simply made a decision(years ago) to use my hardware in the recording chain, and mix 100% in the box. This is even after dropping several hundred dollars on a new tt patchbay, another 192 and all the required cabling. Consider your "needs" over your "wants"
