Hi there,
Welcome to the forum.
Please can you fill in your location on your profile. It helps us all when responding as people may be nearby and able to meet up etc....plus it is also my pet hate and something I am always nagging people to do, thanks
Regarding your self build.
I guess you will be using a 250 litre tank with a small DI cannister.
There are many outlets you can use to get your equipment, I personally prefer to use
www.gardinerpolesystems.co.uk myself as they are always helpful and give advice freely without the hard sell.
One thing I would recommend is getting your tank fixed properly, make sure you don't go over your max weight capacity.
For specific questions please post and the answers will follow.
Good luck, best wishes and once again, welcome to the forum.
Trev