What's "using your two hours at the beginning?" All that you are informing them is that your "uncontactable" as you commute to the airport, with the understanding that in some point in that 2 hrs of SC you'll be in the airport ready to go.

That's bad luck, cause I literally have used this technique about 50 times over the last 9 yrs at different periods when I've bid reserve and have never been denied the early release. I have been put on Sked hold for nearly an hour once and nearly missed my commute flight home, but they answered at the last minute. Sometimes I'll call 3 out and ask about a flight leaving just before the 2hrs and they just release me then, especially if they have already assigned flying to me for the next day.