I would use 5 - 3 - 1 - 3 - 1 - 3. A piece I just learned actually had several very similar phrases in the LH. All 8th notes: A3 E3 C4 E3 B4 E3 A4 E3 - and this same pattern on a few different roots.

But I had started doing it using my index finger on that E3, wasn't really working, and so I found I could stretch my thumb up the keyboard to that C4 much better when my middle finger was on the E. There was even one that went F2 E3 C4, and using the middle finger made all the difference in the world.

One thing you can try is to rotate your wrist inward as you press the E, if that makes sense. Starting with pinky on A, your hand is angled in a way not conducive to going UP the keys. As you push the E, use your fingertip as a pivot-point and bring your wrist inward, that way you don't have to stretch your hand a full 10th. You can buy your self a few more keys doing this. And if you need to go back to the A just swing the wrist back out.

You're not breaking your wrist when you do this, are you?

Nah I'm like a swan, full of grace. Haha seriously though, if you hit the A once at first then alternate on the E and C a few times, what good is it to have your pinky hovering near the A? Especially if it is holding back your reach. It need not be a lurching or convulsive maneuver, but just a smooth rotation of the hand and you can reach a few more keys over.

I'll give these suggestions a shot.

I can very easily reach an octave, I can reach a 9th easily, and a 10th is uncomfortable but doable. But holding my hand in that 10th position to play the figure is extremely uncomfortable. I want to have the upper two notes be between 4 and 1, that is the most comfortable, but was somewhat difficult to do. But I'll check out these suggestions and see what works. Thanks!