chore: tweak parameters for seqdb benchmarks

[dkharms]

Description

I've tweaked some parameters to have saturate CPU utilization (now we almost always use 99%-100% of available CPUs).

I'll bring benchmarks results on my machine to demonstrate better performance.

---

• I have read and followed all requirements in CONTRIBUTING.md;
• I used LLM/AI assistance to make this pull request;

If you have used LLM/AI assistance please provide model name and full prompt:

Model: {{model-name}}
Prompt: {{prompt}}

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 71.59%. Comparing base (8d4e256) to head (d0c23ce).
⚠️ Report is 12 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #162      +/-   ##
==========================================
+ Coverage   71.42%   71.59%   +0.17%     
==========================================
  Files         200      200              
  Lines       18143    18191      +48     
==========================================
+ Hits        12958    13024      +66     
+ Misses       4464     4451      -13     
+ Partials      721      716       -5     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.