[1.7.10] Custom Container andor Special ItemHandling?

[Mecblader]

Hello, I had made a mod that had a custom gui, it was kind of a mix between creative tab and enderChest. The gui was okay, except for three big problems. One, I needed to be able to store more than 1 stack in a slot. Two the code was messy and some parts were a bit hackish. Three, it was kind of tough on low end PC and that bothered me. So, then I saw a few posts on this forum that said that I would have to create some sort of special Item Handling to have more than 64 items in a slot because the default container uses ItemStack. So I was wondering If I created a custom container, with a custom ItemStack class, and tell the container to use my custom ItemStack class, that supports staclsizes greater than 64, then would that be enough or is it more complicated then that. Also my old gui also had 9 tabs that had 468 slot in each of them, I used a complicated system of packets and some slightly hackish stuff to get that too work, is there a better way to do it. I had the idea of having 9 separate guis and then when the player presses the tab buttons, it would open the new gui. I know that this is a long post, but I would appreciate if you could take the time to look over my ideas and tell me if they would work or not. All help is appreciated, Thank You!