-P9mid = [ outside_len - ourcirc_r, outside_gap/2 + ourcirc_r ];
-P8mid = P9mid + [ 0, outend_height - ourcirc_r*2 ];
-
-P89adj = [ 0, P5[1] - P8mid[1] ];
+P8t = [ outside_len - ourcirc_r, P5[1] ];
+P9t = P8t + [ 0, -(strap_above + strap_th + strap_below - ourcirc_r*2) ];