Mystic spells are affected by sdi and slayer spell books (mystic or magery). The reason I say Mystic with a slayer book (lesser/super) is based on a solid suit and template. This is what I run:
120 mystic, focus, wrestling, magery, ei, meditation/resist (i run mediation when in trammel and resist when in fel).
I use 4 faster casting (1 from ring, 2 from bracelet, 1 from spellbook). Every spellbook I carry has faster casting 1 including all my slayer books. The reason I use 4 FC is for stone form. Stone form is amazing in pvm and pvp (much easier to stay alive and get away when raided) but it drops your FC by 2. Lots of solid pvpers will disagree with me on this. But, I mainly use it to stay alive and not kill anyone. I am a defensive/support mystic when in fel.
I have 25 hpi, 12 MR, 10 HPR (+2 from Human) 40 LMC, 100 LRC, 85/70/70/70/70. I run 45 dci, equip a shield for 60 dci and drop my spellbook for pvp. I always have a free hand open for healing stone.
Meditation + focus + 12MR gives you a mana pool sufficient to fuel mystic/magery combos. Combined with the RC and slayer book, it isn't uncommon for me to deal lots of damage within a short amount of time. Plus stone form+wrestling+12HPR+healing stone= tank mage...I can take more damage than even some dexers.
Down side: Because I run resist in Fel, this kills my mana pool, causing me to be much more conservative on my spells against the champ spawn. However, I rarely ever solo spawns. The mystic mage I play is a great support toon in fel and fantastic solo template in trammel.
I have played a lot around with including spellweaving by dropping either wrestling or mediation. I even tested a suit that allowed for 40 meditation and 120 spellweaving. In the end, I found wrestling better than weaving. It really comes down to playstyle. I rarely use protection and I love being able to defend myself without a mage weapon. I am not vulnerable to dexers in pvp because they can't disarm anything. Plus I get the bonus of disarming them with wrestling. The biggest love of wrestling for me over spellweaving is how difficult it is for spawn to hit me. 120 wrestling and 45 dci are wonderful.
Hope this helps.
I am also currently considering a suit with reforging that adds 12 casting focus. I am not certain it is worth it though. Lots of testing to do. But, since I rarely use protection, this could really improve my game play.