How to close disk, again

[Shorrer]

Hello there!
I burned my CD-R disk with... not ImgBurn, and didn't selected 'Finalization'. Then I decided to read about finalization, and it turns out that I need that finalization/closing.

I wanna ask some questions about it, because even after lurking for about an hour or two I didn't found anything really correct.
1. Closing CD disk is necessary if you want it to work everywhere, yes? The disk contains some medical data, and seems that this data will be used only on computer with Windows onboard, but how old that computer can be? Nobody knows. My DVD-RW Optiarc can read disk really well, but will it be okay in old disk drives?
2. Well, somewhere in the internets I saw someone, who said that you don't really need to close CD, how true is that? (I think that guy was wrong, but...)

3. At the end of burning program closed session. In ImgBurn I see two sessions (as disk became multisession because of not being closed after burning), and the only way to close it now is to add some more data and then select 'Finalization', but it still may cause problems because now it is not a single-session disk, but the multisession one. Do I need to close it that way, or better leave it as-is?

4. (optional) Why in the hell CD's have that design flaw? These disks have 700 megabytes on board, so you may find maximum size for TOC. Just offset data sector a little from start, and put TOC to start, and BOOM - here you can burn it as many times as you want, and just add contents to TOC when you add files on disk. Why I am wrong? Yep, maybe there is something that I don't know about disks, because I was always using only flash cards or RW disks because I always get problems with disk. (Nope, I love disks, they're cool, but I almost always get problems with them.)

tl;dr:
Do I need to close my CD-R by writing empty file to it and then closing it, or no?

P.S.:
I know that there already was thread about closing.
Sorry for bad english.

[LIGHTNING UK!]

You can't do it with ImgBurn I'm afraid.