Using Omnigraffle for bathroom remodel plans...?

So… I bought a license for Omni a few months ago but didn’t get around to trying it out til now for a project that is right in front of me – which is NOT why I bought it btw…

So… I’m at the beginning stages of remodeling a bathroom and to get a permit with my local city peeps, I need to submit a few drawings/plans that show what I’m proposing to do. I could go and spend hours learning autoCad but thought I’d give Omnigraffle a spin since I’ve got it sitting here and all – and see whether its up to the task or not. I’m not needing crazy fancy drawings, but need to show an overhead view of the bathroom with the proposed layout of tub, toilet, vanity, etc with accurate spacing per code between items (e.g. 15" from centerline of toilet to anything on either side of it). I also need to do an elevation diagram as well I believe and probably a few other misc diagrams as I proceed into pulling this permit for plumbing, electrical, and general overall tasking.

So… My first thought is to set the grid spacing to 1/4"… I figured out how to setup the canvas to use fractional inches and will proceed from there by laying out a rectangle representing the bathrooms overall space which is fairly small. Are there any best thoughts/practices that anyone can suggest that might have used Omni for similar tasks? There may be other things I want set but am not aware of at this point. Any help would be greatly appreciated!!