details:
-clay soil - topped by 1-2 inches small wood chips & mulch
-about 100 x 40 ft area
-varies from heavy shade in a few spots to light/partial shade - a few spots get full sun most of the day (have about 7 large trees around the perimeter of the yard - which are great during the summer)
-Dallas tx area
-land has slight slop away/down from house - we would like to keep this but level out some of the bumps.

any thoughts welcome - thanks

You probably don't have clay soil. Search for "Jar test" and do that with the photos at 1 minute, 1 hour, and 1 day. That will tell you that you have a sandy soil or loamy but there isn't much clay in Texas. There is clay-ish soil that has excess magnesium in it. That tends to make soil act like clay. There is a soil treatment made by Medina that, if you use too much, will give you that clay-ish soil.

Pick a variety of St Augustine that works in shade and cold weather. Floratam is the really popular one but it is not the best performer in shade. I'm thinking Delmar is a good one but I'm not really that up to speed on the varieties. In general I know St Aug is the one to have in the shade. As a matter of fact I have Floratam in heavy shade and it's doing great, so I can't imagine how well the better shade varieties would do.

When you pull the mulch and wood away, drag a piece of chain link fencing around and see if that doesn't do your leveling for you. It should be at least 4 feet wide and 6 would be better. Put some weight on it so it will scrape off the high points. That tool should do all your leveling for you by removing soil from the high points and dropping it into the low spots. If you need to fill low spots, my favorite material is sand. Whatever you do, do not rototill the soil. That will give you a bumpy lawn that continues to get bumpier for 3 years. You really do have ideal soil right now with the mulch on top.

When you bring in St Aug, it only comes as sod. Roll the sod down with a water fillable roller. Be sure all the sod buts up against the pieces of sod. There should be NO gaps. Good installers know how to fit it in around any obstacle. Down here they use a machete to chop it in. With the really good installations, you can't tell they were just installed.

There are no slow options for shade in the south. St Aug is about the only grass that will thrive. There is one other. It is called Shadow Turf. It is slow to establish but aggressive once it does. It is a variety of zoysia developed in Abernathy, TX along with Texas Tech. I've tried it and am not thrilled with it. It has all the drawbacks of zoysia. The big one that I consider to be a deal killer is that once it goes dormant, it remains dormant until the following spring. In 2011 I made the mistake of waiting for rain so it would come out of winter dormancy. It never came out of dormancy and remained brown all summer. Looks like new, now, but that was a long brown period. Also zoysia cannot fight back against bermuda like St Aug can. So that's the background for why to go with st Aug.