Security Deposit - 50% up front and 50% due before move in?

[Account Closed]

One of my rental units is vacant at the end of June 2015. I'll do some sprucing up during July (some cosmetic stuff) and want a tenant to move in 1 August 2015 at the latest. My property manager started showing the apartment and I got an application. Everything checked out in screening and I gave her the go ahead to get the lease signed. He wanted to pay the security deposit at move in and I said hell no. Then we discussed maybe that he pay 50% of the security deposit on lease signature and the remaining 50% by mid July, and first months to be paid before moving in on 1 August 2015. This was a concession I didn't like to make so I specified that the lease must state that the security deposit (the first 50%) is non-refundable in the event that the second 50% is not paid by 15 July 2015. At least I'd have some money in the bank and 2 weeks to find another tenant.

In general, do you think this was a reasonable, yet sound strategy * or should I have been tougher to demand 100% security deposit paid on lease signing? I appreciate the feedback.

* Legally this is fine to do where I'm from. 

** In the end, the guy ended up renting somewhere else and my property manager continues to show the apartment to other prospective tenants.