I use 3 cytos and two rect. reticles. But I also have 3 sets of kinetic combat and 4 sets of reactive armor. With nothing in range of invincibility I have 29% S/L defense. That alone has made my vuln scrapper playable again. With a herd I get in the lower to mid 40 percent range.
YMMV---IMO
Ice Ember
Single best thing for defense on a /Inv is slot Kinetic combats in your attack powers (u can forget the proc and use the last 2 slots however)
Most Defense powers benefit most from 2 Hami Enzymes, but there are other options, especially if slots aren't a worry.
For Resistance, you'll still want Tough in the build, which should help you hit the Res cap if you want.
Below is a copy of the build I'm currently working towards, and even though it's a work in progress, and much of it is still generic IOs, the survivability with only 30% S/L def and 60% S/L Res is just ridiculous.
Anyway, hopefully it'll give you a few ideas
Hero Plan by Mids' Hero Designer 1.401
http://www.cohplanner.com/
[u]Click this DataLink to open the build![u]
Dark: Level 50 Natural Scrapper
Primary Power Set: Dark Melee
Secondary Power Set: Invulnerability
Power Pool: Fitness
Power Pool: Speed
Power Pool: Fighting
Power Pool: Leaping
Ancillary Pool: Body Mastery
Hero Profile:
Level 1: Smite -- (A)(3)(7)(7)(9)(9)
Level 1: Resist Physical Damage -- (A)(3)
Level 2: Shadow Maul -- (A)(11)(11)(13)(13)(27)
Level 4: Temp Invulnerability -- (A)(5)(5)
Level 6: Dull Pain -- (A)(37)(37)(37)(39)
Level 8: Siphon Life -- (A)(31)(31)(34)(36)(36)
Level 10: Swift -- (A)
Level 12: Hasten -- (A)(15)(15)
Level 14: Resist Elements -- (A)(31)
Level 16: Unyielding -- (A)(17)(17)
Level 18: Health -- (A)(19)(19)(21)(39)
Level 20: Stamina -- (A)(21)(23)(23)
Level 22: Shadow Punch -- (A)(27)(43)(43)(46)
Level 24: Resist Energies -- (A)(25)(25)
Level 26: Soul Drain -- (A)(40)(40)(40)(42)(43)
Level 28: Invincibility -- (A)(29)(29)
Level 30: Boxing -- (A)
Level 32: Midnight Grasp -- (A)(33)(33)(33)(34)(34)
Level 35: Tough Hide -- (A)(36)(42)(42)
Level 38: Tough -- (A)(39)(48)
Level 41: Conserve Power -- (A)(50)
Level 44: Dark Consumption -- (A)(45)(45)(45)(46)(46)
Level 47: Combat Jumping -- (A)(48)(48)
Level 49: Weave -- (A)(50)(50)
------------
Level 1: Brawl -- (A)
Level 1: Sprint -- (A)
Level 2: Rest -- (A)
Level 1: Critical Hit
Thank you for the advice. I will look at my build to see where I can put some of the IOs you talk about in.
I'm trying to make sure I got invincibility slot with the right IOs and getting the most bang for my dollar.
I'm looking at just my numbers in invincibility, nothing else.
Here how I'm slotted: Four LoTG( def/end red/Rech;Def/end red;Def/global recharge bonus;and def), one hami o: Cyttoskeleton, and rectified reticle: increased perception.
Can I get some advice on what I need to do or how to fix my defense? Thank you in advance.