Best practice for panels beside sidebar.

I use panels with a 12 column grid. But on every page I have some sidebar blocks (managed by context module). I don't like to turn off all drupal blocks neither to disable the sidebar blocks for the panel pages, because this means to configure them on each panel. Instead I prefer to use panels and blocks/regions together. Now I am wondering about the best practice.

My idea is to clone the panel layouts and modify them to fit in the content region. For example the content region has the width 9 of 12 columns used beside on grid-3-sidebar. Inside the panel I want to have something like first column 2/3 and second column 1/3 of width. So I was thinking of cloning omega_12 to omega_9_of_12 (with grid-6 + grid-3 columns or with grid-7 + grid-2 columns). Is this the way to go or am I overlooking some better features?