My first thought is that, as far as I know, Sunn never made an amp called the Spectre. I'm guessing that you mean the Sceptre.
I've used a Sceptre and a Sentura II many times, for both guitar and bass. They're really nice little amps. Not the same as the Model T.
My Model T is a second generation (2G) model. I didn't like the sound all that much until I did a couple of mods to it.
The Model T has four 6550 power tubes, and is rated at 150 watts. The Sceptre has two 6550 power tubes and is rated at 60 watts. That sounds like a big difference in power, but it's only 4dB. You could even pull two of the T's tubes to make the power output almost identical. (Note: this affects the output impedance of the amp. I don't recommend doing it if you don't know what you're doing.)
The Sceptre, Senturas and their ilk have reverb and tremolo; the Model T does not. There are other differences in the preamp circuitry that make the T sound different from the Sceptre and its clones. So, they're not going to sound the same. I don't know what kind of sound(s) you're looking for, but I'd think that you could make the smaller amps work. They might even be better.
