One workbench, three related computations: event-market linear PnL (settlement vs strike), margin health (unrealized PnL, buffer, liquidation price, leverage) against a venue margin model you declare (regulated-DCM or offshore-perp class, with its own initial/maintenance margin rates rather than a built-in per-venue table), and, when you add a second position, two-leg correlation-VaR cross-margin efficiency. Closed-form approximations of the same computations live risk engines run, not a stress-grid margin system, and not financial advice.