With recognition that I am not the most experienced with the proposed scenario, I have come to learn that having compatible gain across all components in the system is always a concern and I would agree that this can be even more critical with tube gear and sensitive speakers.
Not so much with tube pre/amp combinations, though there are many tube pres that IMO provide too much gain. Especially when using high output DACs.
The concern would be greatest with tube phonostage as they generate the greatest magnitude of gain.
