Go sit in your bathroom (your home bathroom). If you have a large box or something that can stand in as a "wall" or "vanity" that you can move fairly easily, that's even better. Place your barriers where you THINK you might want them. Get a measuring tape and have a sit. Stand up. Adjust your barriers. Do it again. Don't forget the elbow room for "wiping". Where would you put the TP at? Act it all out. Don't forget to drop your drawers and pull them back up (it's the standing up/pulling your drawers back up that may surprise you at how much room it takes). Just like a shower. Act it all out. Then you may want to factor in the "hugging the toilet" act.
Compass Rose dimensions:
Wet room (toilet and vanity sink facing each other): 50" x 25-1/4"
Vanity: 12-3/8" deep x 25-1/4" wide x 34-1/2 H (top of vanity counter top) Counter top has front overhang of 3/4"
Toilet (residential) w/round bowl: 26" front of bowl to back wall
Bowl to front of Vanity: 11 sans doors because I haven't gotten them made yet.
Accordion door on the 35-1/2" entrance. Door is easily removed in case the toilet needs to be removed to replace/repair.
Going from the RV toilet to the residential toilet lost us 1-2 inches on the floor space in front of the toilet, yet the drain was a perfect match.