So for our prep work we should be looking for at least one guild bank (if not more depending on how much gold you have to spend). Depending on how many slots are available, you are looking at an investment between 500-750g. This might seem like a lot (many people who message me are sitting at the 10k to 20k range for investments) but just Investing in Netherweave by itself will recoup that loss and more.
Lets assume that you purchased a 3 tab guild bank. That will give us 291 slots to play with (3 x 98). Thats a good healthy amount of slots to store items for quick flipping and production. If your working with one guild bank (which I suggest placing at least two of your crafting toons in). Organize your tabs with one tab covering one profession. Tab 2 can cover the other profession with tab 3 being organized over miscellaneous items to sell. If you have purchased more than one guild bank then repeat the process with two more toons (if you have them) or seperate your toons so that each bank is covered by one of your production toons.
This setup will allow you to go directly to the guild bank to pick up items instead of needing to log out on one toon to ship items to the other crafter. To set this up will require a trustworthy friend/player who you can set as the Guild Master and invite the other one of your toons into the Guild. After the invite and acceptance then your friend can return the mantle of Guild Master to one of your toons.
Organization is going to be a key ingredient to being successful. Those first few days will go quickly with people looking to invest gold into items. They will want to buy more and more items and it's a guarantee someone will be there to purchase them. The important part is to make sure that the seller is you at the highest cost possible.
Good Luck and Good Hunting