Maria, it can make a difference that fast for sure. Many of us can tell when E hits. And if I have bad symptoms (such as my attempt to move to Sandrena a few days ago!) and I put some gel on, in 90 minutes I'm ok again. Sore boobs I don't think would happen within one day... 
I think sometimes the jitters are due to surges from our own ovaries and there's not much we can do about that because if we try to reduce HRT, by the time we've done that, the surge has gone and then we are low again. Sometimes I think taking a higher dose of estrogen during peri is actually a much better idea - because higher doses switch off our ovaries more. Just like the pill does. Then you avoid the peaks and troughs of what we make ourselves. I think we still make a low amount but the ovaries are not really active....  Another approach might be taking a progestin only pill as well as HRT (they are licensed to be taken as birth control whilst on HRT). This will also stop ovulation, make our ovaries quiet down and stop pumping surges out.... Just a couple ideas anyway.