Best wifi extender for Nighthawk x8 R8500

Hi,

I am looking to extend my wifi network to get over deadzones. My nighthawk x8 is in my basement where both the Verizon ONT and a large number of wired connections throughout the house terminate. Repositioning the router into one of the other rooms that are wired wouldn't work without adding a second wire to run back to the basement to a switch.

I am looking to get another netgear product to compliment the x8 and I think that means I need an access point but I think I really want one that is not a wifi extender that is going to halve the bandwidth but rather one that can run from one of my wired rooms. For example, the family room on the 2nd floor is probably as far away as I can get from the x8 and would be an ideal location since that is where I am suffering from the most deadzone issues. The single port ran there is shared using a Prosafe GS108E managed switch with a number of devices. I think I just need to get an Access point that I can plug in to the GAS108E - is that correct?

Another requirement is to be able to run the same SSID as the x8 does. I have read elsewhere that as long as the access point is on a different channel to the router, what should happen is that the any client device that accesses from either the x8 or the access point will be on the same IP network (the x8 will still be doing DHCP). Ideally, it would be great if client devices would flip from x8 to the access point without the IP address changing, just going to the wifi source with the strongest signal. 

I have listed the EX7000 as a potential but I don't know if this is the best product for my needs or not.

I only bought the x8 last year and although I have read good things about the Orbi I am reluctant to spend another large amount of money.

Any advice gratefully received.