Ok, i've looked at the FAQ, but it didn't really answer my question, if i missed it, just give me a link.
1st question: Ok, for side editing, what do you do so you wont have a HUGE file size like 200 mb ( i think this might be answered in the FAQ but i would like a better explanation.

2ns question: Well, the basic thing is not having a huge filesize as a side, 200 mb etc.

I would like it explained here please....

Remove what you're not needing from the side's REQ file.

That's it? just the req file?

If I recall correctly, the REQ tells VM what to munge. If something you don't need isn't in the REQ, it won't munge, hence it won't increase your filesize.