Any idea what I should gun for?

Look here for the best possible affixes/suffixes (multiply them by 0.75 to see whether they are rlvl 30 or under):
http://classic.battle.net/diablo2exp/items/magic/pre.shtml

Depends on build ofc. But an ideal ring would be something like:

- 120 AR
- 5 repl
- 90 mana
- 30 resists
- 9 str
- 9 dex/ 20 life / 5 dmg

Those numbers in brackets are the lvl req ?

Omg thanks so much, all those 6 mods could spawn?

Yup

Thanks for helping out. I know what to look for now.

Any idea if 2offensive aura could spawn with 2os and visio for lvl30?

Yea, ofc.

You should study the link posted above, almost all is covered there.

Those numbers in bracket is the lvl req in that link?

Take that number, multiply by .75, round down to the nearest integer if it's not an even number.

example, ilvl 10 * .75 = 7.5 lvl req, which the game rounds down to 7.