Adam Jones' tone on Schism is dark, heavy, and mid-focused. A Les Paul in drop-D tuning through a Diezel VH4 and Mesa Rectifier blend creates a massive wall of low-end with enough midrange clarity to articulate the complex time signature changes. Jones uses minimal effects, relying on the raw power of the guitar and amp for his huge sound.
Both Marshall Studio Vintage 1×12 and 2×12 cabs run open-back Greenbacks. Both pair with the SV20H. The 2×12 is twice the cone area, twice the weight, and a different room experience. Here's when it's worth it.
The Celestion V30 takes a beating in modern djent contexts, and that criticism is fair. But in the medium-gain rock zone (Marshall plexis pushed to breakup, Bluesbreaker-stacked Twin Reverbs, AC30 territory), the V30 is still the speaker its 1990s reputation was built on. Here is when to choose it, and what it does that nothing else quite does.
Two Studio-line heads. Two of the most modified Marshall preamp topologies ever shipped. Which 20-watt version belongs on your board, and which one actually sounds like the amp it claims to copy.