Demon House:
script: 4 months
drawing: 4 years, still going
Heavy Horns:
script: 3 months
drawing: 4 years, still going
Sarota Springs:
script: 3 months
drawing: 2.5 years, still going
Erie Waters:
script: 1 month
drawing: 1 year
Secunda (webnovel)
writing up to 57,000 words: 4 months
Of course I'll tweak and edit comic scripts as I go and draw, but that takes only a few hours at most if I really need to rework a scene.