Note (lovelily99): As a Level 37 Crafter, items I craft using Vacuum Core have +14 HP Drain/hit, so the question mark for the Level Category should be somewhere from 32-37. I believe at Level 38, items have +15 HP Drain/hit.
Note [felineDD]: As a level 34 crafter, I already make items with each Vacuum Core adding +14 HP Drain/hit. Therefore the question mark is either 33 or 34. :)
NOTE:[PKMON] You can only use up to 3 cores in some crafting and hp drains stuff maxed is only 50 of hp drain and the color of wine red from blessed spark is glitched turning it to citrus orange (lovelily99: when you try to make a wine red sun glory shield). More from lily-Basically, if you craft an item that already has default hp regen (dragon horn armor, mithril chunk shield, etc.), and you add more hp regen by infusing blessed spark, it will be okay for you. BUT...if you trade that item to someone else, the added hp will go away, and if you chose the Pink color from blessed spark, it won't be there anymore.
Note 2: Maxed effect for anything is 50. Also, you can't dye the item unless you have 3 DIFFERENT infusers. Exceptions are dragon horn armor (the ones with HP REGEN, so not the WINGS) or anything with an effect built in, like dread biter (confusion) or a life stealer crossbow.
Note 3 (note 2 extended-ME AGAIN, it's LILYYY)-For every item there's a description right? Then there's a silver bar and then an effects section. There needs to be three effects in that section for the item to be dyed the color of your choice. So you would need three different infusers for the three effects to be present. But things like dragon horn armor, and things said in Note 2 have a built in effect. You can use 2 of the same infuser and one different one and still get a color to work for that (special effect + effect of first infuser + effect of second and third infuser which are the same = 3 effects total).
HOWEVER, you have to be careful and make sure the special effect of that item is located in the first section, right under the item description. Items like a masamune (mithril chunk 2H sword) adds AP, so you might think you could use two repeat infusers, but it won't work, because the added AP is shown somewhere lower in a different section of that item's description, closer to the weight, durability, etc.
I hope I didn't confuse you. Ask me questions in game if you need help! -lovelily99
Note 4: It seems at level 22-24 I crafted a sword with Dragon Horn, and Minotaur Hide that gave 11MP drain, and 4 AP drain. (Feel free to correct this, but I added an extra bar of level to level 20 materials, (Most of which is guess work) and also corrected some minor things. So please correct anything I may have gotten wrong.) -AkiraHiro