How to choose a toroid core and wire size?

I'm planing to build a receiver for 4mhz or 7mhz or 14mhz.
Have not decided yet.
I have not worked with toroids before.
It seems that for 500khz - 30mhz I should use Red E cores.
There are 24 of them to choose from! They all have u = 10.
**broken link removed**
Color me confused

How do I choose?

While I'm asking Questions, how do I choose a wire size?

Thank you for any help.

See if this helps.
Ferrite information by dxzone.com

For wire size read this.
https://www.electro-tech-online.com/custompdfs/2008/12/Toroid_Wire_Size.pdf

Thanks Mikebits. That's a lot to wade through but it's not an easy subject I guess.

Thumb rules would be nice