(n00b) Help with Detect Power

[onetrikpony]

* Did google, faq, and forum search *

I'd like to build a "Detect Magic and Psionics" sense power for a class of characters. I'm kind of stumped using the Size & Speed/Range table for Sense Roll modifiers.

This is how it should work:
* The power allows a character to "sniff out" magic Items, people who can cast spells, & people who can use Psi powers at a base range of 50ft.
* The power allows a character to detect active magic and psionic events; spell casting, psionic power use, active magic items, at a base range of 400ft.

My basic questions:
1, Does the S&S/R table apply directly to sense rolls? (it seems a little short ranged for vision rolls; 50% chance to notice a person standing 2 yards away?)
2, are these powers modeled better by Increased Range modifiers or Acute Senses?
3, How is the effect of Increased Range (sense) 5x (+20%), different than 4 Levels of Accute Sense [8] ?


What I've got so far:
Detect Magery >0 (occasional) [12]; (Increased Range 5x +20%)
Detect Active Magic Use/Effect (rare) [8]; (Increased Range 50x +50%)
Detect Psychic Talent (occasional) [12]; (Increased Range 5x +20%)
Detect Active Psychic Use/Effect (rare) [8]; (Increased Range 50x +50%)

Thanks for your consideration