16km Landscape 2Km tiles or 1Km tiles ? performance?

Hi guys just wondering if anyone has any idea which would perform better… I know its kind of an impossible question. I’m doing an open world island with tiled landscape looking to set my performance to last gen consoles like the ps4 xbox1 (no mobiles, no Vr) and Pc’s with same performance, as the minimum spec. I plan to have all maps loaded in at once using world composition using 4x LOD’s static meshes so only 1 landscape is used at once (Max 4 landscapes if crossing a corner) … so ether 256 x 1km tiles or 64 x 2km tiles … I would like to use the new water system But don’t know what the max landscape size is before it stops working? know it doesn’t like big landscapes can’t find out how big?

My main worry is Spikes of lag and Popping in late when loading landscapes in at 2km tiles (2017x2017 res) but I can be more aggressive with LOD’s…
but then if I use 256 x 1km tiles (1009x1009 res) there is 256 of them causing a lot more work for me and Pc would need to load more levels in…
But what would cause the biggest hit on the Pc / console ??? any tips on what something like a Ps4 / Xbox1 can handle better or max performance in verts / Mb