Introducing a budgie to others?

[DMC]

I had two budgies and one died after only two weeks. I got another one so that the first would still have a playmate. I introduced them in the same cage and kept a close eye on them and they bonded almost instantly. By that night they were snuggled together and sleeping. I was wondering, because the cage I have is soo large, and because the cleaning and care dosnt seem to be a big deal, would it be ideal to get maybe one or two more? How much MORE time would i be looking into spending and how will these birds get along if two have been in the cage for about a month.

If it helps, the two i have are just BEGINNING to come around. Still very frightened but are getting used to me being in the cage everyday for feeding, watering etc.
Yes, i was hoping to tame them eventually. About how long would it take to tame them? A matter of months? Years?