@JJ6 At that size, spermathecae should start becoming visible on a female, so snag the next molt if you can to confirm the sex 100%. I personally find the epigastric furrow itself to look too lippy/feminine to say without doubt that your T is male, and I've had multiple vent-sexed male Poecis surprise me when they molted out female.
And please, if you don't mind - after you DO confirm the sex of the T, if you remember to, please come back to this pic and comment what it turns out to be for posterity's sake.
@Arachnophoric I'll try to figure it out but it's naughty boy (or girl) and usually takes molts into pieces. Anyway he will stay with me until maturity so I'll post a comment here when i'll be sure about sex