Fixed Attentuation On A Speaker Cab?

[doveman]

I would like to back off a 2x10 speaker cabinet just a bit 3-4 db when it's running in parallel with a 1x12 cabinet. I don't really need adjustable attentuation. Maybe a DPDT switch and a LPad (Driver Attenuation Circuit). This appears to be one resistor between the speaker (R2) and one on one of the leads (R1). I found a place that has a calculator where you put in the Ohms and required db attenuation and it gives you teh values of the resistors. For example:

Z = 8 Ohms
A = 3 db

Parts List = Resistors
R1 = 2.34 Ohms
R2 = 19.39 Ohms

My questions:
- Does this work well?
- What kind of resistors would you use for 35 watt amp. (When it's being used in parallel the amp power would be roughly half that ... not talking a big amp.)
- How would you get these specific values ... how close can you be I wonder?

I have an old Altair that works OK with the 4db setting for me but just curious ... lot of weight to carry around just to use the first setting.