Going Back To A Bi-Amp Setup...Need Advice

I once had my system set up in Bi-Amp mode using a Class D Audio 470c for the woofers on my Revel F52`s and my Rogue Atlas Magnum for the mids and highs and it worked nicely.

After awhile I felt as though I really didn`t need all that power for the listening levels that I like, so I sold the 470 and have been running the speakers full range through the Rogue ever since.

But now, I want to do it again but to my knowledge few amps have adjustable outputs like the Class D Audio did which was pretty useful in dialing it all in.

I want a different flavor this time around to power the woofers otherwise I would just get another 470. 

An amp like the Parasound A21 would work, but I wonder if there is a way to add a outboard volume control so that I`m not forced to only shop for an amp with adjustable outs ??

And also...is a Class D amp (design) a better candidate for this arrangement ??  They have gobs of power and are cool running to boot.