5 Speed Gear ratio advice?

I agree those splits are pretty nice for a 340....67-.73-.77-.69od. Very nice progression.
I am somewhat surprised tho that you're not complaining about the lack of starter gear, or the fuel mileage at 65=1900rpm,lol. I'm guessing if NA that you're running a fairly stout cam,and or some mean heads,lol. With just an 8.59 starter, I'd have to guess heads?

So what range is a good starter gear?

I think I like it high, just so I can put it in first gear and chug along while idling in bumper to bumper L.A. freeway traffic. I can't do that with my 2.66 first and 3.23 rear. :( It starts to buck if I try.

As an example... My '16 Tacoma has a 3.98 first gear and 4.30 rear gears. I can idle in first gear at 3 MPH. Perfect for freeway bumper to bumper traffic! Of course, the tires are much taller than the Duster though. I'm sure fuel injection helps too.