I would much prefer you select 7700 than turn without permission. The squalking ident idea above if you have that amount of time is a good starting point rather than going in full tilt, but some of the weather recently hasn't been that predictable. If you turn without permission, I definitely want you to get 7700 on, but I'm sure there are many out there that would disagree. All to do with each individuals airspace and their constraints, what works for one may not be best for another.