I have a three Deco X60 setup for mesh wi-fi in my home and that's working fine. But I also have about half a dozen wired devices (ethernet) incl a few PCs and a network printer. My ISP is Frontier FiOS and I have the FiOS router with its wi-fi turned off, since I use the Deco system. Problem is that my wired devices are on one network (192.168.254.0/24 supplied by the FiOS router's DHCP server) and and the wi-fi devices are on a different network (192.168.68.0/24 supplied by the Deco DHCP server). I'd like all my devices to be in the same Class C network space so, for instance, the wireless laptops can see the wired printer, file shares hosted by the wired PCs, etc... Note that my ISP "point of presence" is in my study, where the FiOS router and the main Deco X60 are also located. I also only use FiOS for internet access, no TV or phone service.

Here's how I thought I might solve this: Use the main Deco X60 in the study as my router/DHCP server (get rid of the FiOS router and plug its "upstream" ethernet directly into the main Deco X60). Use the second ethernet jack on the main Deco for a TP-Link TL-SG108 8 Port Gigabit switch and plug all my wired devices into that switch. I thought that way the Deco would be the only DHCP server in the environment and the only router, so everything would be on one Class C network space provided by the Deco. 

Alternatively I could have the main Deco as the only device plugged into my FiOS router and use the 8-port switch as described above. But I was wondering if that would offer any advantages and if I'd get in a double-NATed situation ?

Ideas ?