Visit the Yanfly Channel at:http://yanflychannel.wordpress.com/rmvx/
There is a download for the Y6 Core Engine script, which is a simple plug and play. Just follow the rules of where to post it in the script editor, as I belive it should appear before other Yanfly scripts.
This script fixes everything wrong with VX, from items to menus and battles, and even the variable bug. It also tweaks several other things as well. It also resizes the screen to 640 x 480 (min tiles 20 x 15). I haven't had too many problems with using this.
Off topic, but I think having this script pinned here for VX along with the Yanfly Channel will go far in assisting new VX users. The comment on the site reads:
"What’s posted here is for public use. Whether or not you use decide to share it with others, post it on other websites, use it in your own games (free or commercial), I’m okay with that as long as credits are due to their respective parties."
So posting it here would be acceptable as long as credit is given.