Some of the fascia boards behind the gutters is rotten and needs replacement. What are appropriate lumbers to use? Also, should it be primed and painted before it is installed, or after? This is an 80 year old house.

Some of galvanized gutters are rusted through, and it seems like its beyond simple patching. Location is in the Sacramento River delta, with the occasional hard rain. a. What gutter length can one downspout drain? If I keep the same style of material, I'd have 2" downspounts and hope to drain a 33 foot length. b. How acceptable is it to reuse 2" round downspouts, as opposed to the rectangular ones? c. there is theissue of whether to use galvanized (DIY) or Aluminum (ot DIY?). Opinions? d. If using galvanized, the insides need to be painted. Does anyone use epoxy paint for that? Seems it would last longer. Thanks! Able