TenBears

I'm glad everyone is finding this guide helpful.  Myself, I find some of it quite confusing...

e.g. this.

Suppose you have a 10", f/5 Dob. You will have a focal length of 1250mm, and will get 200x with a 6.25mm eyepiece.

In practical terms, a 6.5 to 7.5mm eyepiece will be what you will find available.

Yep, I totally get this.

This though

To get a 5mm exit pupil out of a 250mm mirror, you will need an eyepiece that gives you 50x. This means a 25mm eyepiece.

To get a 7mm exit pupil out of the same mirror means a magnification of 36, and a 35mm eyepiece.

And then there is this

If you can afford slightly better eyepieces, then buy those, with the length guidelines still in mind.

Exactly what, constitues "better eyepieces"?

Not really much in this guide that explains the differences in eye pieces?  This is just mostly talking about mm.