Generally, almost all audio systems have TOO MUCH Voltage gain, resulting in various combinations of not enough volume-control range, more electronic noise out of the speakers*, etc. The most-common culprit is too much gain in poweramps and secondly too much gain in linestages.
Nelson Pass recognizes this and makes one of his FirstWatt amps with NO Voltage gain--yes, it's just a 'preamp-output buffer', converting the preamp's Voltage to the same Voltage but lots higher current to drive speaker systems.
Dgaylin, your goal of more than 100 tubed Watts for your 86dB-(in)sensitive speakers seems reasonable to me, but I doubt if you'll find an amp with little-enough gain (such as maybe 10dB). Using the 4-Ohm taps will indeed lower Voltage gain AND increase speaker-damping factor compared with using the 8-Ohm taps. The easy thing to do is try the in-line RCA/RCA attentuators.
I just bought Monarchy SE-160 poweramps that use a 12AT7 for frontend gain and a class-A-biased output stage that uses MOSFETS. With the designer's approval, I'm now using 12AU7s, and the amps have c. 9dB less gain. About 10dB still-less gain will be about right, and I'll have to get that by changing something within the amp or adding a resistive dividing network at the amp's frontend.
IF you fall in love with a tubed amp that has too much gain, a technician can fairly easily add a gain contol at its frontend.
* which is more likely to occur with relatively hi-sensitivity speakers
