First of all, there are two kinds of separation drills. One is a drop in the dungeons and you can find it in player's shops. I think there is still a chance of failing with that- never used one myself so I'm not sure. Then there is something called the Perfect Separation Drill in the Item Mall. It costs 400 points but using it guarantees that your gem will come out intact.
Currently B7's are cheaper than most imbued scrolls with +30 charm but keep in mind that you can only use B7's in 5 spots- the accessories (ring, earring, necklace), the body armor, and the weapon. For the rest of the items, you'll be using the substats. I've used B7's on both of my FS clerics in the spots where the gem can be placed because it was less expensive. You can get a Servant's Look body for fairly cheap. The whole set is only 100 pts in the IM or you can find someone selling it. Then if you put a B7 in that- the body would be done forever.
For the accessories, maybe get the level 75 charm set from the NPC in Eucar then add +30 charm substats on it. Since you can use substats from grade 1 items on there, it won't be very expensive to do. Then just use that until you can equip the Beautiful set (lvl 160) and at that point I would gem the set with B7's.
For the gloves, go kill trash in Sunshine Coast until you have 30 pcs then talk to the NPC on the beach and get the Moldie Innertube for free. It has 30 base charm and then all you will need is the +30 cha substat.
For the offhand until you can use the Mummy Doll (lv 220), get an artisan to craft you a bunny doll, either with the +30 cha sub already on it or put one on it yourself after. It has 16 base charm so with the substat you'd have 46 which is more than enough until you can use the other offhand.
Hat - tho the Shamrock is the best with base charm of 40, you can find a Leprechaun Hat for decently cheap. It has 35 base charm. You would need an event substat for it but even just using the hat itself is better than nothing until you can get the substat.
Shoes- Unfortunately there are no good shoes with charm base stat but the Yellow Boots are only 100 pts in the IM. It;s a good investment if you want to equip your cleric so it will have decent charm
The Summer Backpack should be available again when the Summer event starts. You can get it from doing the Scavenger Hunt. And for the mask, use Style Glasses with 50 base charm until you can get the Heart Frame Glasses.
If you're on Draconis (or can wait until we merge), I can craft the bunny doll and the sunglasses for you. Just let me know