In 1/72, PE would be just fine. At least at a guess.
The bar armor was 3/4 x 3/4 x 1/8 angle stock (20 x 20 x 3mm) with 5/8" (16mm) reinforcing bar, which was stood off 12" or 18" (30 or 45cm) off the hull.
Now, at 1/35, you are right at where the "upset" (the raised texture) on the bar would "show"--this is what was frustrating in my ancient attempts.
That 20mm angle iron is about 0.6mm at 1/35; at 1/72 only 0.2mm.