This is my two cents worth...
My interpretation is a lure is a concentrated odor product usually the result of blending very odorous and permeating ingredients formulated into a desired lure base.It then is generally aged for a period of time. This aging process allows for thorough blending and permeation of the ingredients to achieve a desired end result odor. The final product is then expected to provoke interest or entice a curious behavioral response from a particular target animal.
Lures can be curiosity, food, glandular or reproductive cycle marking scent lure types.
Lure usage generally only requires very small amounts to achieve the desired result per application at a set. Drops per set use for liquid products and a Q- Tip amount for paste type lures as a rule.
Baits can be described as two types from my experience.
1) Natural edible or man made materials such as raw meat, fish, food grade stuffs or fruit type baits that can be used fresh or aged. These baits can be used as is whole, ground or chunked up for your desired use preference. Use amount can vary from a little piece to a larger chunk depending upon the type of set it will be used for and the amount of odor you want to push at a particular location and set.
2) The next bait type I refer to as loaded baits. These generally are accessible meat based materials such as bobcat, beaver, venison, beef and/or various small game animals round out your bait choices. These meats bases are then processed and blended with various essential oils, glands, urine, fish oils, skunk essence and other desired ingredients.
In essence these formulated baits are in themselves a form of lure. Once you add several ingredients to a meat it completely transforms the original meat into a loaded form of bait. These baits if well built are extremely effective. Understanding the type of bait you are using will help to guide you as to the amount you will use per set.
Loaded baits can also be used in small amounts like a teaspoon size as a reference to use amounts. Follow the recommended use by the maker on the product label. In time you will be able to establish your own use amount per set. Maybe more or maybe less.
Location is the prime key in helping to determine lure and bait use amounts.