Power Reduction

Personally I think that you're going to need more power reduction than just 1/2 power to be useful, maybe not, but probably so. With that said I think you would be happier by using a power attenuator like a Hot Plate or Marshall Power Brake.

In our band Myles plays a 1974 50watt Marshall head through a Peavey Classic 4x10 cabinet and he uses a Power Brake to cut the volume, we've done this for the last 15 years or so with great results. He generally plays with it about 3 clicks down from max with each click being approx 3db or 1/2 the power of the level above.

Now maybe if you play outdoors or in a very loud band things might be different cause a lot of those old Peaveys are VERY LOUD. Mace, Duce etc, talk about an amp that's built like a tank, never blows up and can be bought cheap. Great sound if you want to do Skynard, nothing better if you're willing to crank it up:^)