FortiLink Topology Suggestion

[dur]

Hi folks, I've the following topology and I'm trying to get FortiLink working the best I can, I'm reading the supported topologies on the manual: https://docs.fortinet.com/uploaded/files/4080/managed-fortiswitch-563.pdf But can't find anything that fits my needs, the closer one that fits my needs would be the mode: HA-mode FortiGates managing two-tier FortiSwitches with access rings.

I've been thinking then to do a classic standard managed way (cisco kind of), but I'm struggling to make those 108Es do the trunking against the 200Es, plus they don't suport L3 routing, so... anyone has been on a similar situation, which topology, logic would you suggest in here? Thanks!

[link]https://imgur.com/a/qvujx6D[/link]