I have done some multi-family, custom and production work.

Ask if they have any issues that you may be able to address.I treat tenants as customers and have empathy for them - give them some leverage when they fall on hard times - but be firm and let them know that this is your business and you depend on the rent to keep your operation running.There are times when you can supply the tenants with up-grades, Frig, new stove micro wave - with those items supplied you'll be able to increase their rent a little.Treat your tenants with respect - thy are your customers and their rent pays your mortgages and gives you an opportunity for a wonderful cash flow and future retirment.Cheers

I want him to value me as a customer and continue to feed me deals.  

The GC's I know seem to be geared towards more high end/custom home finishes.

Always do the math analysis and try to look at your prospective properties before you make an offer on it or have a clause in the sales contract of the subject property some upfront time (about 10 to 15 days) to make a detailed inspection of the subject property without a penalty that will hurt you too much.You may or may not have noticed yet, but be aware that that there many crooks on the Internet that have been specialists at selling stuff you do not need.  

However I had a  prospective tenant say they had 5 cars for two people so it happens.

They need to want to help you and return your phone calls promptly.In the begining especially, alwaye do a math analysis and try to look at your prospective properties before you make an offer on it or at least have a clause in the sales agreement that allows you the time upfront (about 10 to 15 days)  to make a detailed inspection and possibly back out of the deal without a penalty that will hurt you too much.  

I have found this to be an advantage in certain circumstances where the customer knows they are dealing with a professional. 

But are those unsecured loans automatically disallowed to be part of ones deposit - or does it depend on how the customer's relationship is with the Bank?

I mail merge with a printed letter on letter head and address the envelopes with a custom font thru my Brother printer.