[InSteady]

flaxseed has an atrociously low smoke point (225 F). You really shouldn't be using it for cooking whatsoever, let alone seasoning cast iron.

In general I agree with your sentiment though. Find something that works for you and go with it.

[arcanemachiner]

I don't mean for my salty comment to justify a not-ideal method. But for this topic, the proper use of the pan will generate a good seasoning as it is used.