Hello 25/F - Not Sexually Active BMI 29.9 (TFTs Normal)

Hello
25/F - not sexually active
BMI 29.9 (TFTs normal)
Currently not on any medication, never used any OCPs.
Diagnosed PCOS
(Elevated free Testosterone & DHT)
Hirsutism
38-40 day cycle (regular BUT prolonged- since menarche up untill 6 months ago it the cycle length was around 27-30 days)
Ovulation occurs around 24th day ( prolonged proliferative phase)
Currently working on losing enough weight to get <25 BMI and since it will be a gradual process, off of DIANE 35 & PRIMOLUT-N which one should I take to treat this ongoing oligomennorhea? What dosage regime is recommended for my case?
I am a fresh medical graduate and will highly appreciate an educated discussion.
Thanks.