"expert" install option for slackware-current?
 

I need to limit the packages pretty much to "required" because of lack of space. Is there an option that would run a script that would give this option (like in the iso versions) for slackware-current?

Also, is there anything that would enable me to eliminate/choose packages that are already installed? (Showing which ones are optional etc.)

They're all optional - some are just more optional than others. ;-)
Seriously, have a look at the tagfiles (maketag{,.ez} in each package set - that should get you started down the right road. Alternatively, you could just install the A/ series, and then start adding things you know you need, look at ldd(1) output to figure out what those things need, rinse and repeat, and until you finally have a fully working system. In all honesty, you'll likely find that the practical solution will be a mixture of those two suggestions. :-)