Should I try to use the IE implementation of CSS Grid Layout?

If you are using Grid in a very simple way, and positioning items rather than using auto-placement then the fact that grid exists in Internet Explorer from version 10 could turn out very useful. You could certainly use this in order to create a simpler layout for IE10 and up, once Grid is shipped in other browsers.

However be aware that this is going to require some additional testing and work, you are unlikely to be able to simply rely on Autoprefixer to run and do the work for you. For example, if you have used auto placement for any item and then don’t set a position using the -ms properties, that item is going to stack up with any other unpositioned items in the first grid cell.

The good news is that the IE implementation is pretty much frozen in time between IE10, 11 and current versions of Edge (presumably until Edge updates to the new specification). So work you do to implement grid in IE should work in those versions without needing to do different things for different IEs.