Upgrade path 5.2.10 to 5.6.5 or 5.2.10 to 5.4.9

I am planning and preparing to upgrade my FG200D HA cluster (2 units). current version is 5.2.10.
 
Question 1) Do you guys find the support.fortinet.com upgrade path tool reliable?
I ask this question because using the tool for 5.2.10 to 5.6.5 is kind of weird (5.2.10 > 5.4.6 > 5.6.3 > 5.6.5)
I was thinking (5.2.10 > 5.2.12 > 5.4.9 > 5.6.5).  I just want to make sure I avoid the IPSEC bug in the upgrade to 5.6.4.
 
Question 2) Would you risk 5.6.5 or stick with 5.4.9?  I don't have any zones in 5.2.x do I don't think I need to worry about the zone VLAN interface bug. I would like to use the 5.6.x feature that allows address objects in the policy routes.

I think (not sure) the tool is showing just one possible upgrade path simply based on the fact that each step of the upgrade is supported, without considering in what kinds of bags are with the version, which might break previous config depending on the features configured and used.
Based on the assumption, I think (again) your educated discretion is necessary to modify the entire path from the one given by the tool to avoid some particular upgrade problems, by checking each step using the same tool since that information is no longer provided with release notes.
 
At this moment, at least I don't have any problems deploying 5.6.5 IF we didn't have zones with the parent and vlan sub-interfaces. Practically it's impossible to upgrade those FGTs in the field. However, that's the only issue holding us from upgrading the whole fleet of our FGTs. Others in the forum might have different opinions (likely).

Thank you all for the feedback. I have been testing my upgrade at my desk on some similar hardware. My team decided we would go to 5.6.5 on 8/28/2018.
 
5.2.10 > 5.2.12 > 5.4.9 > 5.6.5   seems to work fine. All the config errors during upgrade seem to be minor things (dashboards, snmp, etc...)