Please help me confirm these are the FortiOS versions I want to use before I configure...

Hi Everyone, 

I have to setup 2 Fortigates to be VPN linked across the country for a company's 2 different locations. 

I have a 30D - Currently at v5.0, build 0292 (GA Patch 9)    and 

I have a 60C - Currently at v5.0, build 0318,150514 (GA Patch 12)

* I will be using Point to Point VPN to link them. (Preferrably IPSec) 

* On the 60C, I will use both WAN ports and want the failover (when WAN1 falls down) to work and respond fairly quickly -- assuming the Point to Point VPN link will reconnect over WAN2 out to the 30D automatically? Please confirm that as well. 

* Behind the 60C I have an office full of 10 to 20 users that will be using the Internet and web applications that are hosted through the VPN link to the 30D's network.

* I may setup VPN for end users on the 60C but I don't want to stress it. At most there will be a small handful of home VPN users (5 or 6 at most. Usually 3)

My main question is:  Given my main goals, above, what version of the FortiOS do I want to use on these devices?

I have a support contract on both, so I am being offered (through Fortiexplorer) to upgrade to 5.0.12(build 00318) or 5.2.5(build 00701) on the 60C  and I can go for 5.0.12, 5.2.5, or 5.4.0 on the 30D.

Thank you - appreciate any rapid replies since I'm supposed to be working on this for the weekend...