i have a few different species at that size and one P. regalis that i am very certain is male.
This one is a bad pic but it has a fairly broad area above the epigastric furrow, that is no darker than the area below and has a clear, slightly white lip all the way across.
could be sexual dimorphism shows later than in other poecilatheria species but these are by far the largest followed closely by my P. rufilata, one of my P. metallicas and my P. regalis. and i do think its harder to sex females for certain unless you have seen a clear male first
i have not been able to have a peak at the ventral side of my second P. subfusca "lowland" sadly ...