If this works you could basically send a BoE to your 80/85/89, let him enchant it with whatever enchant and then boost it to 90 and send it back with the enchant intact + BoE?
Like BoE leggings with a Golden Spellthread for lower levels. Or Scorched Leg Armor on BoEs.
Like, I got a pair of Ruby Shades with ZG Enchant soulbound to me on my 85, if I bring him to 90, could I get 1000000000000000000g for it?