partitioning - Preparing HDD partitions for dual boot

I've got my Dell Inspirion 5558 with preinstalled Ubuntu 14.04 a few days ago. What I don't like is that the HDD, which has 500GB is not partitioned as I wanted(as expected), so now I have one extra large partition with Ubuntu installed on it, a swap partition and three additional primary partitions made by manufacturer I suppose with boot loader, recovery partition and stuff like that, so right now my hard drive looks like this

HDD(500GB)

• sda1(500MB) - primary, FAT32, label: ESP, flags: boot


• sda2(40MB) - primary, FAT32, label: DIAGS, flags: hidden


• sda3(3GB) - primary, FAT32, label: OS, flags: msftdata


• sda4(454,41GB) - primary, ext4,


• sda5(7,82GB) - logical, linux-swap

First thing I want to know is are there any reasons why I shouldn't erase everything from HDD? I don't know are any of first three partitions required for my lap top to work properly, although I suppose that while reinstalling Ubuntu all that is needed will be created and I really don't think I need a recovery partition as Ubuntu is free to download and use. I don't see the problem with starting from scratch, but as I said I am new to Ubuntu so better safe then sorry right?

Here is what I want. I want to have a dual boot system with Ubuntu 14.04 and Windows 7, but I don't want to install Windows right now. I just want to prepare the HDD partitions so I can reinstall Ubuntu(yes I want to reinstall it actually, so keep in mind that all partitioning will be done while installing Ubuntu) and leave partition for Windows to be installed in the future. Here is the partition scheme that I came up with and which I'd like some of more experienced users to evaluate.

HDD(500GB)

• sda1(150GB) - primary, FAT32, Mount point: none, for Windows


• sda2(30GB) - primary, ext4, Mount point: /


• sda5(120GB) - logical, ext4, Mount point: /home


• sda6(195GB) - logical, FAT32, Mount point: none, for data for both


• sda7(5GB) - logical, swap

Device for boot loader installation: /dev/sda

So here are my questions

1.Should I maybe create another partition(if yes which primary or logical) for boot installation, and how big should it be, or will it be taken care of with this setting? I saw it got 500MB, but only used around 30MB.

2.As I saw I cannot create partition as a NTFS, so I assume I'll have to change FAT32 partitions to NTFS later, perhaps when I install Windows. This is more of an observation then a question really but feel free to correct me if I'm wrong.

3.Are partition sizes OK or should I allocate memory in some other way?