@scovar, Sparkle’s canvas has been evolving nicely but as you are aware it doesn’t do rulers. For me it is something I wouldn’t use as I don’t lay out my layout in a mathematical way.
Sparkle does have grids though. You can set this as per device.
You will find it at the top of Sparkle’s UI - 4 vertical lines grouped together. By clicking it you will see you can turn on or turn off the grids.
There is another way though if you feel rulers are important for you to create your website.
You can build your website out in Sketch with rulers and all, and when done import it into Sparkle…