Nearer the time, if we still only have a BETA or RC in sid and serious bugs, we may decide to just stay with 10.0. If a BETA or RC is *already* in testing, we may want to ask the release time about getting a pre-approved unblock when the final release comes.
I am afraid, that we have to decide our goal much earlier. Especially w.r.t kfreebsd-kernel-headers (it b-d on kernel source). Iff we go for 10.1, we should ship pre-betas into sid during August. Petr