Finally got me some RVS (= stainless steel) bolts with UNF thread. Got them new on an oldtimermarket. Now I only have to shop for the 8-32 tapered and threated "crossbolts" I need a few of them for the low windshieldframe.
doorlock B-pillar: 6x rounded head bolts 1/4 UNF 16mm long (incl head), (5/8length, GRade5 strength).


low windshield frame: 4x bolt-ring-nut 5/16 UNF 30mm long (1.1/4 length) incl hexagonhead. Also 8x 3/16 UNF 5mm long incl head witch is tapered head. Also 5x? 8-32 (or called "10") UNC 7mm long with tapered head. Also 2x 8-32 (or called "10") UNC 9mm long with tapered head. And 6x 8-32 (or called "10") UNC 8mm long with tapered head


doorhinge bolts: 32x 1/4 UNF 16mm long incl hexagon head. (5/8 length, Grade 5 strength).


if you got a tip where to get the smaller tapered "screws" (they don't need to be stainless steel), let me know.
ONLY NEED THE REARLIGHTBEZEL SCREWS, don't know the size yet. (Paul Wells could deliver them from http://www.datsun-roadster-parts.com