40 minutes - 2 hours
Speaker was dead on used phone what I bought, so decided to fix it rather that taking back to seller.
Repair was quite straight forward following your guide.
The only point where little thinking was required was the relocation of the new speaker. The location is not defined exactly by surrounding parts, so you can install it sideways slightly off, maybe 1-2 mm if you don't look carefully how it originally sits. And since it attaches with adhesive tape it might be difficult to relocate once put on place.