Tracy,

I think you'll find plenty of information and opinions in the threads shown in the link below. It's the results from searching for 'dwarf spacing' in this forum (which should cover dwarf and semi-dwarf varieties). As you'll see, a big factor in spacing will be pruning.

The cedars may present a problem from CAR (cedar apple rust). Since I'm not familiar with the prevalence of this disease in your area (and can't even tell where you live because you didn't include that info with your zone info or on your member page) , you might want to contact your local ag extension service for more locally-relevant information on that.

If you want to supply your location, you might be able to get more information about CAR here, from someone close to your area. You may also want to do a search from pruning techniques. You'll find numerous threads on the topic (maybe to the point of overload). Once you've done a little studying on that, come back and ask questions to clear up any concerns you still have. I wish we had one single, really thorough thread about pruning, but unfortunately the information is pretty scattered.

Finally, have you researched varieties that will do well in your area? That may be a "can of worms". If not, your local extension agent might be able to give you some initial ideas on that too, but you'll definitely want to supplement his/her recommendations with your own research.

Here is a link that might be useful: Search for 'dwarf spacing'