Firstly, you need a female Zweilous and Male Charmander to breed Deino as the babies species is determined by the mother not father.
Secondly, if you're going to use Ditto as parents, why not just make them breed straight away with the Zweilous and cut out the Charmander in the meantime?
Thirdly, the destiny knot passes down 5 IVs from both parents regardless of who is holding it, so the offspring can get a combination passed down from either parent, this isn't restricted to perfect IVs either, so you can still inherit junk IVs as well.
If for example you have your Ditto 1 breed with Zweilous:
Ditto: 31/26/13/10/8/31
Zweilous: 15/16/2 / 5 /6/28
Hypothetically the baby could be:
31 / 16 / 13 / 10 / 6 / 20
It inherited 5 IVs from the parents, the one that didn't get inherited got generated randomly. You've just gotta keep doing this until you get both the HP and speed from the ditto. According to this calculator you have a 17.1875% for that to happen. Then you can change Ditto 1 for Ditto 2. Except trying to go from 31/x/x/x/x/31 and x/x/x/31/31/x to 31/x/x/31/31/31 is only a 2.3438% chance. If you hatch a 3IV Deino (6.6406% chance) swap that for the Deino parent. Then to go from 3IV and 2IV parents to a 4IV baby is 4.6224%. So it takes a lot of patience and a lot of hatching but you'll get there eventually. The very first breeding project is alway the hardest because you don't have good parents to start with. The best way to get a jump on it is to look for stuff for trade. People send out their 3-4 IV offspring they don't need over WT so you could get lucky there. Otherwise you could ask around here if anyone has any good parents. I might even have some good deino from my breeding project with them!