this guide might help
http://forum.videohelp.com/threads/163978-...ORKING-GUIDE%29

imo, it is easier to just convert to avi/mkv and use external subs. a lot less step needed.

if by timing you mean video/audio sync :
-unless you're encoding separately, you don't have to worry about it since most software will "do the thinking for you" . you can encode to 23.976 or 25 or 29.97 as it will not screw up you original movie lenght

if by timing you mean the video/subtitle sync :
-most type of subtitle you'll found on the net is *.srt, and *.srt uses time-based sync, not frame-based. and it is quite easy to sync the timing to your video, should one need to be. just use any subtitle editor for that.

should need be, you can PM me.