BHK preamp in HT mode and Amp matching

Looking for Users and PS Audio experts advice regarding using BHK preamp in HT mode and use With McIntosh Monos @Paul.

Is it set to full gain and still usethe tube gain stage and improve the sound? Or is this completely by passed?

Does it supply enough oomph to match well with Mcintosh Mono blocks particularly MC1000 that likes 2.5 volts supplied?

Has anyone driven big McIntosh mono blocks with the BHK preamp and their opinions on match?

I read output on the BHK preamp is only 4.0 V olts RMS where MC1000s are getting 5.0 Volts from my current McIntosh pre amp.