Add Quantity Tier Pricing To My Admin and Website

My website is [login to view URL] I need to have in my admin where I can set up custom quantity pricing like if someone orders 6-12 or 13-50 they pay a lower price similar to what one of our competitors did [login to view URL] In my admin this should be an optional field and I should be able to input the quantity ranges and prices and have them displayed on the product pages This should be bug free after it is setup if someone adds a product to the cart for example 12 quantities it should take on and show the new tier price in the cart. You must set up a test I can not have any downtime on my website. I will also take seperate and combined bids for 2 similar projects Setting up an optional custom field for the products where a customer can get their name or text embroidered on (also similar to something like happy chef has) Setting up a few optional fields where I can input what the field is and the selections for example if I want to add this product to my website [login to view URL] I do not have a field for coat lengths so in the admin if I had an optional field I could type in coat lengths and the add the selections but this field would be optional and for a different product the field might say something different if I wanted it to if that makes sense. If you feel confident and can give me a good price on one or all of these projects please pm me and I will give access to the admin and plesk so you can take a closer look.