I haven't played much dual pistol yet but I think I can help a little on the Radiation Emission set having built a rad rad corr, rad rad def, mind rad cont all 50s and now my fire rad L40. Can you tell I love the radiation emission set?
Anyway,
Radiant Aura is your heal, pick it early
Radiation Infection is one of your two main debuffs...again pick it early
Accelerate Metabolism is team buff...as soon as possible pick this power
Enervating Field is your second main debuff
Mutation sometimes doesnt make the cut...i love to rez my teamates but most of the time it just doesnt matter as the hospital is always an option. stupidity hurts sometimes. If you cant bear not to rez your fallen comrade fit this in
Lingering Radiation is a third debuff that slows opponents in a cone...i never take it
Choking cloud is awesome 6 slotted with purple hold set. yes. take it.
Fallout. Gee...another power that is only good when your teamate is dead in front of you in the middle of an agry mob...I will pass. Having a pseudo vengance for damage is kinda fun when they think you are rezzing them...and you arent...hehe (same animation for mutation where it picks the dead body up in the air and then , in this version, puts them back on the ground where they are still dead! what fun!)
And EM Pulse. I hate EM Pulse for killing my blue bar temporaroly...but dang is it effective as a mob stun or blue drain. I always end up with it in my final builds.
So minimum is 6 powers to be fairly controllish, 8 to help the team with rez and more mob control.
I recommend tough and weave and maneuvers for any of these type toons. Staying alive is a big deal.
Enjoy making the AV's defenses like paper mache with your debuffs. 
I would add that one of the best things you could do is slot RI for -tohit as soon as you can, be it teaming or soloing.
If you take and slot both RI and Suppressive Fire, you'll pretty much have zero problems soloing.
Must have powers (with minimum slotting):
Rad Infection (max -tohit)
Accelerate Metabolism (max recharge)
Enervating Field (2 endurance reduction SO equivalents, though I would recommend putting this off till after stamina still)
Lingering Radiation (2 accuracy and max recharge. This one is your AV killer and low-mid level crowd control power, though the slow component is buggy for corrs right now).
Nice to have and slot:
Radiant Aura (you don't get a choice, but if you are slotting this then you want 2-3 heal and end red. in here)
Mutation (nice on teams, though only a "must have" if you do a lot of high risk stuff)
EM Pulse (2-3 hold and accuracy in here)
Fallout and Choking Cloud aren't bad as well, but I'd say they fall more into personal tastes.
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I'm going to chime in here and note that Choking Cloud is probably a reasonably skippable power. There are builds out there that include it, but indicate that it's an all or nothing power. Either skip it or grab it and six-slot it for utility. For me, I wouldn't plan on taking a power that essentially requires six-slotting to become useful.
On DP, you can probably wait for a little while on Swap Ammo if you haven't gotten it yet. The need for the secondary effects really isn't necessary until you've got some damage to use it with, so don't feel you have to jump on it immediately at lvl 6 (or whereever it opens). Note that most of your attacks in DP have an innate acc bonus (1.10 vs 1.00), so slotting can be a bit less painful. Slapping a Damage Proc in Pistols doesn't go wrong, and if you can afford to grab an Achilles Heel (-res) proc, do so. Present opinions suggest that Empty Clips is probably the most skippable power in the set (or at least can be respec'd out of, or eliminated on an alt build).
Suppressive Fire... I'm not sure on this one. I've got my DP/Rad at 35 and haven't taken it yet. I might take it at this point but it'll be situational.
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Suppressive Fire is more important if you solo a lot, when you can't rely on teammates to shutdown or distract trouble mobs.
RI will give you huge soloing survivability on its own, but with SF you can slap those trouble mobs like sorcerers and illusionists.
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I started a Dual Pistols, Radiation Corruptor. I really like her, but I'm not sure what powers I should be choosing for a working and well rounded build. I would like one that could do solo if NEED to, but also, one that could team very well. (Mainly Team) If someone could give me some advise, it'd be much appriciated. =D