Not trying to hijack the thread, but I have some questions about this. When you say "jump up" to the SPI/Double Agent, why do you use that term? Aren't the Alphas supposed to be Ride's top-tier bindings?
I say "jump up" meaning jump up in flex. The Alphas, although stiffer than Deltas, are still a freestyle binding. It's a part of Ride's MVMNT line which stands for "movement." The highbacks and chassis in the MVMNT line of bindings allow for more flex. So even though the Alphas are fairly stiff, they give when tweak them. That's a freestyle quality.
The SPI and Double Agent have stiffer highbacks and chassis that still give when tweaked, but not as much as the MVMNT line's chassis. Also, the SPI and Double Agent are stiffer with an ankle strap that comes with inserts that you can use to customize the flex.
So that is why I said Jump Up to the SPI or Double Agents in regards to all-mountain riding. All-mountain freestyle, Delta or Alpha... All-mountain freeriding, jump up in stiffness to the SPI or Double Agent.