They call me the Deranged. I'm an aggressive rider. I guarantee you that there is no pace you could set that would have you not finishing this century. Now, whether an early hard pace would have you finishing slower than a more even pace is very much harder to say, and really quite immaterial to your training goal. You don't have the experience in your body to tell. I can "titrate the pain" very precisely. I have ridden, at 60+, centuries where I did every climb near threshold and still finished quite nicely, though utterly destroyed. I advise going for that experience. It's called "learning to suffer."
Watch your HR. If it drops below what it should be for that RPE, eat more, immediately. Keep eating until it goes back up. If your HR is higher than it should be, drink more, immediately, and continue until it goes back down.
Eat on the bike as much as possible. Practice riding in the drops. Keep your elbows and knees in.
Assume you can do it and go for it. Recover between climbs. That's faster than taking it easy on the climbs. Shelter behind wheels, especially if you feel tired. Look for every opportunity to recover. If you can outclimb the group you're with, drop them and look for another group up the road. If they drop you, find a slightly slower group.
Enjoy the physicality of it. It's quite the trip and addictive. Don't have a goal time or speed until you get close to the finish and know what you're capable of. Then surprise yourself - if you can.
Even going really hard, you should be able to recover muscularly in 3 days, hormones in a week. Meaning that you can start riding again with maybe one day's rest, just easy to start with until you see where your body's at.