My speaker's impedance is 8 ohm. The reason that I thought to add a attenuator so I can use the whole volume pot, because how I know if the volume pot is only at 25%, then it won't have that good of a tone like at 75%. I know that this is kinda true at valve amps, but I don't know if it's true at SS amps.

I'm new to building amps and pedals but I'm currently working on my first amp project. For the preamp I'm using Rod Elliott's project 215 (40W version of project 27: https://sound-au.com/project215-p27-revisit.htm ), for the power amp I'm using a TPA3118 class D amplifier and for the speakers I'm using a 10" Celestion Ten 30. I was thinking to add a switch where I can switch between 30W and 1W and after some digging and asking, I found out I need an attenuator, but after looking into the forums here, I've seen some people say that you don't need an attenuator for a solid state amp, so I'm a bit clueless on what to do now.

The use for the amp would be for home practice, pedal making and testing (main reason) and also occasionally use it for jam sessions with a friend of mine.