Stay with fin or switch to dut

[Plan C]

I have been taking 1.25mg Proscar for 4 months now. I went through the shedding phase; this has now stopped. However, my hairline is continuing to recede. Shall I hang in there with finasteride or switch to dutasteride? People will argue that 4 months is too early to see results but shouldn't finasteride reduce DHT levels regardless of the length of time you have been taking it for?
Both my father and my mother's father are completely bald and I'm not sure finasteride is enough to prevent me from accepting the same fate.
Note: I use Regaine twice daily + Regenepure DR and NT daily.