brim for warping ABS

Very often I use slic3r for my projects. If I need a brim under my prints, slic3r makes it in parallel to the outline of the object. If the object warps and its corners will lift up from printbed while printing, this kind of brim breaks and so it is useless. So I have made a lot of rectangles X,Y differs and Z=0.15mm. I print this first, then the object
On difficult materials I use this printbed (bottom to top):
heated bed
glass for flatness
sheet of iron to support magnets
painter's paper tape (good product. noname doesn't work good)
ABS juice (blue at this photo)
printed brim
when object print started, some magnets around (e.g. magnets of old CD drives or small flat loudspeakers)
Adhesive of the paper tape doesn't work good at temperature. Magnetic field works at every time. Long parts starts warping, but they do not remove from bed while printing. Normally I use ABS/PS blend, it makes more warping than commercial ABS filament.
I have made tests with p