It only takes a couple long days to fully load up everything, EQ, balance, etc. But I do agree that you will most likely tweak your template forever. Little volume balance adjustments here, EQ tweaks there. I recently completed a new 250-track orchestral template, but I know it'll take half a dozen tracks or so to get it to where I really want. My previous template (which I very recently used) is roughly 3-4 years old and I was STILL making adjustments to the very end. To me the hard part is getting a healthy overall/global volume level of the template and keeping it organized. When I'm sequencing, I work like my hair is on fire and tend to arbitrarily load up new patches for new projects, paying no heed to patch labeling and routing organization. After a couple years of this, your template can end up a mess.