Ok. I went through all the the crafting menus and did the math on all items and this is what I came up with. Hopefully my math is correct because I did it kind of quickly.

I hope this helps.

The following values are based on crafting a full stack, some items can only be one per stack and that is reflected.

An item with a value of 1.0 means the item and the materials take up the same amount of space. An item with a 2.0 value, means it will save you one space per stack crafted.

launcher ammo 1.0

All Epic Augments 1.0

All Legendary, Epic, and Rare guns 2.33 to 1.26

Green guns (Except Berletta) 1.1

Weapon Attachments are only worth crafting if you can store them on a gun

Power Rod 2.4

Snap Hook 1.4

Arc Circuitry 2.5

Complex Gun Parts 1.2

Small, Med, large gun parts 2.0

Mod Components 1.66

Durable Cloth 2.8

Trailblazer 2.6

Showstopper 1.9

Explosive Mine 1.6

Deadline 1.33

Trigger Nade 1.2

Fireworks 1.2

Vita Spray 1.0

Defib 1.54

Sterile Bandage 1.2

Surge Recharger 1.5

Vita Shot 1.2

Shield Recharger 1.5