Attn: robbat2, not bbullock, sorry -- Gentoo questions

So here I am, finally getting around to installing Gentoo on an extra disk in babylon5, with the intention of migrating over to it altogether once I get it set up how I want.  Right now, I'm still running my Gentoo environment chrooted under my 2.4.31 kernel, until I have it fully set up.  Only, so far I'm running into a few setup problems I can't find answers to.

• I can get emerge to build Perl with ithreads enabled by placing 'dev-lang/perl ithreads' in /etc/portage/package.use.  I cannot get it to build Perl with ithreads, use64bitint, and uselongdouble enabled; it ignores all my attempts to do so.  How do I make it play nice in this regard, and keep doing so?
• Every time I emerge a package, it gives me a list of dependencies it will install.  Among this list, invariably it tells me that before proceeding, I should update portage to sys-apps/portage-2.0.51.22-r3 before proceeding, and that I can accomplish this by emerge -u portage.  When I then execute emerge -u portage, it tells me portage is up to date and there's nothing to do.  What's with this?
• All the documentation seems to indicate that udev, unlike devfs, offers no mechanism to address a device as (for example) /dev/sd/c1b0t5u0p4 instead of /dev/sdd4.  I hate and despise the /dev/sdx model; it's horribly broken, it's lame, and every time you insert a device, you have to figure out which other device identifiers are now going to point to different devices than they used to.  (I am in fact totally gobsmacked that, by kernel 2.6.14, Linux still uses the /dev/sdx model at all, even for legacy support.  I repeat and emphasize, it's HORRIBLY BROKEN and should be considered harmful.)  Is there any means that the Gentoo installation handbook just isn't bothering to tell me about, by which I can tell udev to use fully specified device identifiers that I can safely rely on to always point to the same physical device?