I haven't done Big Ring but I've done the climby parts, although I squared off that part where you turn from Nohl Ranch Rd to Imperial/Cannon. That part is pretty steep (13% if I recall) but it's not terribly long. Santiago Canyon is long but not terribly steep, but it's an oven out there. Whatever climbing there is seems to be pretty front loaded, which is always nice. That's generally the route I take whenever I ride from home to one of the zillion soccer tournaments in south OC my kids are always playing in.
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Beachgrad05 did it last year (I think the metric), maybe she'll chime in.