This is the suit of my "seeker" character (male gargoyle) which I convert to treasure chest hunter, sunken chest hunter aka fisher, honesty-lost item hunter, dungeon chest picker etc. with soulstones. It is not optimized for t-hunting specifically but for the "seeker" character (i.e. aforementioned "seeker" templates I am converting this character into using the very same suit and equipment).
I am using a 50 SDI book from a "treasures of event" for non-slayer mobs and a set of "invasion event" super-slayer spellbooks (and alternatively a set of juonare grimoires with bloodwood talisman in wraith form) or a balakai staff (wand version) if I am taking damage. I also carry a dragon slayer spellbook for the ancient wyrms and cold dragons/drakes which spawn quite often. I do not do many maps in Eodon and Ilshenar because of the general spawn and because you cannot mark runes there. However, I do carry a set of anon spellbooks for Eodon as well as a shadow wyrm costume (with the polymorph totem) for the changelings in Ilshenar (so I can use my dragon slayer book to do triple damage on the changeling). The totem also allows me to keep on "flying" as a gargoyle, thus moving at mount speed to outrun the changeling or a paragon ("flying" does not work with the equipable costume, you need the totem for it). Note that I do not want luck on the suit because I prefer clean items with a few "right" mods over brittle or antique with many mods.
When I was starting this character, I was doing t-maps using the deluxe armor suit (for gargoyles) from the store and the blue jewelry set from the cleanup reward vendor. I do not see much of super-huge difference between this expensive suit and the suit from the store (which is fairly easy to replicate with common loot), that's why I said it should not be difficult to get gargoyle gear for a caster. Also, as I said above, while invasion super-slayer spellbooks are difficult to get now, you can just use a set of juonare grimoires (some books I bought for 50k on VS). One good thing about the old suit is that my other gargoyle character, which is a fighter, can still use it to get into form or cast buffs like protection (as it got 100% LRC, is blessed, and light in weight) after resurrecting or soulstoneing as well as do shard transfers with it (as it is not shard bound or character bound). On that note, as Pawain posted above, making a gargoyle suit for a dexxer is a completely other story.