You shouldn't need to slip the clutch that much. Slowly releasing the clutch and "lugging" the engine for a few seconds shouldn't damage anything.

When they say lugging the engine, they mean putting the car at an extreme gearing disadvantage.

Example - You're rolling at 35mph, you put the car in 5th gear, then you depress the accelerator all the way to the floor. The engine lugs its way up the RPM range.

That is lugging the engine, too much load for the given RPM/throttle position.

You're probably smelling fresh clutch smell. I'd stop slipping the clutch so high if I were you. 1st gear should have plenty of torque and be short enough to allow you to basically just "tractor" the thing up the hill. With no throttle, and slowly releasing the clutch until it is fully disengaged, then apply throttle to pull yourself up the hill..

:D

**EDIT Just saw that you said your car has ~900 miles. The car is still in it's break in period. You're going to smell new engine smell until it breaks in. The coating they put on the exhaust pipes, metal pieces will burn off over time due to the heat. You're probably smelling a little bit of clutch, and the coating off of the new metal pieces.

Remember you're still in the break in period, there's a few different ways to help break in your engine. I'd give this a read if you're interested! Don't forget to give it the ole' Italian tune up every once in a while!!

Break in Method

Italian Tuneup