I think we are all getting a bit over-complicated here in terms of a take-off alternate and wind. As far as JAR go, the '1 Hour at s/e speed' is a NOMINAL figure for planning purposes only of no consequence to the actual time taken to fly to the alternate. (I'm sure we've had this discussion recently elsewhere on PPRune!). There is NO requirement to take wind into account. IIRC it is actually predicated as a still-air distance in the regs. That is not to say that if your chosen alternate was 1 hour (still air) away into the teeth of a 180kt hurricane it would not be prudent to consider that.