Pretty good but in my opinion the key feel to your customer table should remain as record ID. That way if there is a slight change to the customer name in the future everything will stay linked.
Why is it that you feel you need to change the subject to be the customer name as opposed to the record ID. My suggestion is to leave it out for record ID and just fix any conditional drop downs so that they work off the record ID.
Of course the other thing that goes without saying, but I will say it, is that you obviously make a copy of your after you make these changes. There is no cost for making a copy of the app.
You are probably right that the links to the records in the trail table which is in a cross application relationship was offering, but as you said there's only 10 records so you can link them back up manually.
