Best way to pull wire

You are using relatively large conduit, but I wouldn't bet on pulling it alone.

With the information given I would fish the LB to detached garage first.

If you use a small cable or rope to pull through the PVC sweeps it can cut through them.

Some general advice:

Run the long stretch first, coming out of the LBs at each end, then run your stubs to each panel. You really need 2 people, one to pull and one to feed the wire into the pipe. Otherwise you will be doing a lot of running back and forth. I know guys who squirt a little lube in each piece of pipe as they are assembling the run. The main thing is to keep the dirt out.

What happens if dirt gets in there?

Dirt causes drag and makes the wire harder to pull. Always try to pull wires into conduit downhill if possible. It's better to have gravity working for you instead of against you. It does make a difference.

It will create extra friction and make it harder to pull.

I use a fish tape, but I've never tried such a long run. Wire lube also makes a huge difference. Whatever you pull it with, make sure it's attached securely because if it comes loose 90% of the way there you'll be kicking yourself.

I use tensile force. THAT is the BEST WAY to PULL wire.