As a solo tank, you'll have to borrow some from Tyr setup, because you'll need to deal more damage than normal. After you get higher level, or wealthier, you can then change to true Sigel setup. Don't worry about losing value. Tyr items generally carry a higher price tag than Sig items, so in the end you'll get a return on your investment. Just to start...
1. Enhanced Shadow Cutter. It gives you everything you get with Enchanted Exalted Cutter, but you get 450 attribute damage.
2. +8 R99 Bloody Heavy or Light set. If you go light, you can always tweak your skill tree to get more p.def, if you need it.
3. Cloak -- Best way to improve damage and survivability. Elmore works fine, if you can't find a Ferios.
4. Radiant Circlet -- Prices have dropped for these, so should be easy to get.
5. La Vie en Rose jewels (normal, not Greater, unless you can afford them) all level 4 and at least a 5 stone brooch.
6. Talismans - Longing is nice, but Insanity is better. Talisman of Protection can be bought at NPC and enchanted up to +4 at least for more p.def. Guard Agathion Charms are also a fairly cheap way to go to get more p.def. If you wear Heavy armor, you need Masia. If you wear Light armor you need Paulina. Someone mention 7 Signs. It's ok, but for 11-12b, it's way overpriced for benefit. There are other ways to get the same results spending less.
7. Bracelets and Agathion - If you're lucky enough to find one of the old Taurus agathion bracelets on sale from someone, buy it. Otherwise, go with the new seed bracelets. Stage 2 - Stage 3 is all you need. Then you can equip multiple Agathions that boost p.def, p.atk, crit damage, etc., as you see fit. The Exalted bracelet works fine in the short term.
8. Artifacts, artifacts, artifacts.
9. Enchant skills and learn Forgotten Skills.
10. If you haven't already done so, make a Dual Class and learn skills at least up to 105.