Lets see I've done Death ride (fun ride)
Climb the Kaiser (those who do this poo poos the death ride)
race around the bear (timed 100 miler going up to a ski resort... over 7,000 ft of climb ??)
breathless in agony ride (another 100 miler with lots of hill climb)
and others.

Unless your ride has 10-15% grade, I wouldn't spend too much time on such a grade. Training on such hill doesn't seem to do much except to just grind you down. Instead concentrate on doing 5-8% grade over longer stretches. the 10-15% grade do appear on Death ride and on Kaiser pass but they are really short. On Ebetts (death ride), you find them on the switch backs. On Kaiser, its after the big creek and it lasts only 1/2 mile. And if you are used to riding 15 miles sections with 5% grade, you wil handle the 15% grade without too much difficulty. I wouldn't say its easy. Its doable. To a runup to you big event I think it would be prudent to ride a 75-95 miler rides with 7000ft climbs and repeat it maybe five times. During the week, you do need to add a rest day. You also need work on strength and endourance. Your speed on flat may decrease somewhat so don't be alarmed.

Also if possible train at altitude. You can lose more than 10% of your strength and stamina at altitude. Otherwise don't psyche yourself out of it.

Lots of luck and don't give up.

The secret of great hill climbers are they are all really tough mentally. Psyche first then physical.

now do take my comments with grain of salt cause I'm not a coach nor claim to be trainer. just my personal experience.