The fg57 would fly the sig rascal very well with a cylinder poking out each side,don't forget to allow for the offset when you cut the cowl.That engine is based on the 'old' 300 nitro twin and if you've ever bench run one of those you will know how much i look forward to a 360 version if they ever make them.You'd be bulk buying nitro if you did'nt think seriously about cdi and straight methonol.I'd run nitro because i like the animal that that lets out.
ps captain shush up or you'll have sr batting on about cdi for months