Ultimately, it comes down to developer preference, and how you and your team determine what to be consistent doing. Someone else could respond and tell you the complete opposite and it wouldn't be wrong, really.
Personally, I like separating the grids into their own specific forms so that their purpose is explicit and easily definable.
Also, it becomes easier if you need to change an aspect of how the data is being generated for each one. Over-optimization is easy to do when you are starting out, so make sure you aren't purposely complicating things more than what's essential (accidental complexity).
Furthermore, you are going to run into a ton of these scenarios, so I think separating your grids/forms into distinct pieces will make it easier to organize your project (use folders!).
OK thanks. I'll use different forms and try the form loader.