Thanks a lot buddy
It helped a lot.
Well I've just started to test the option (I don't have a 4GB USB so I've setup a 4 GB partition on an external HD - same thing).
I've maned ubiquity and then saw that there were no options regarding the installation size (was expecting it, but when thought through I think the devs already tried to make it as small as possible), so you can scratch the option of using the installer on a USB smaller than 8 GB (or if the devs have some suggestions of course).
Still, you can setup a 4GB USB using unetbootin.
Btw, I've just checked my 8GB USB (sdb1 7GB, swap 1GB) - after the installation 4.76GB of sdb1 were used. Now after a couple days of tinkering with it 5.8GB are used.
So I don't think that there is no proper reason to use the ubiquity installer on a 4GB USB because you are sure to eventually run out of space.
I can confirm this, that 4Gb aint enough anymore for install, so I had to install BT4 to 16Gb SSD (my second hard drive) on my Asus 701 4G. I think I will install some small standard Linux distribution to 4Gb SSD, that can be used for "normal" stuff.
If I were you and this were my first time with linux then I would go with something easier like straight ubuntu. Since you will probably just ignore that piece of advice then go with the automatic partition editing instead.
As for swap on a usb not unless you want the usb to fail faster.
Might want to read up on that last bit.
Google=swap partition, read-write cycles usb
Generally speaking if you have more than a gig of memory you don't really need a swap partition.
4Gb aint enough anymore for BT4, so you need to get at least 8Gb stick now. Unfortunately most oldie eeePC's have 4Gb fast SSD and now it wont be enough for BT4. So I just installed it on my second SSD drive (16Gb and unfortunately slower but still reasonable speed) on my trusty Asus 701 4G
Might install some small linux distribution on that 4Gb drive now for the "normal" stuff...
just hope the noob doesn't have more than one SATA hdd...and it's identified by /dev/sdb...
Anyways, I prefer the "extract iso to root of pendrive", run "/boot/bootinst.bat", verify that the drive letter is the same as the pendrives', check for errors and boot the damned thing...
(It doesn't get easier than that...)