Rena, this sounds like a good start - then you can customize it according to what you're doing for each client (if necessary) - or relative to whichever package they have chosen.
There is a per-project contract in the Contracts Pack that might be useful in this case.
And one quick note - when clients are contracting you on a package basis they're not necessarily going to expect you to track or justify your hours. A lot of that part of the relationship is based on how you establish things in the first place and help craft their expectations for what will happen going forward.
Good luck!