It depends on how much gold are you going to spend.
mana orb + garb + tangle + renjuv cloak + lt sash = 8 MR + 15 DCI
you can craft a shield with SC (no penalty) + 2 MR + 15 DCI
There are very good and very cheap artifacts that I use in any mage suit:
Enchanted Kelp Woven Leggings: MR 2, SDI 8, CF 4
Crown of Arcane Temperament: MR 3, SDI 8, CF 2
You can use as well:
Protector of the Battle Mage: MR 2, SDI 5, CF 3
Pendant of the Magi: MR 3, SDI 5
But I myself don't use them because they have low intensity and it is difficult to maximize resists with just 2-3 crafted leather items.
So usually I use the crown + the leggings + 4 crafted/imbued items.
I imbue resists, lmc, lrc, mi, hpi on this items. As a result I get all those stats (including 25 hpi) maxed without jewels.
Jewels depends on "misc slot" artifacts and on book. Usually 2/6, 15 DCI + what you need (EP if you want).
The total stats are:
2/6, 50 SDI (75 with a scrapper), 45 DCI, max resists, 150 int, ~200 mana, ~140 HP