Remember to include your finished countertop overhang in your calculations. If you have a 1 1/2" overhang on both sides, you have reduced your 39 down to 36. That may be a bottleneck - depending on your layout. We have 42" between range and prep sink - that is comfortable but allows room for two people to pass. Around the rest of our island, we have 48" (countertop to countertop). It allows plenty of room for people to pass - even if there is a group chatting around the island. Very important when you entertain!

We used cardboard boxes taped to chairs to mock up our space. Because of that mock up, we gave our walk ways more room - and sacrificed a little drawer space to do so. I am so glad we did!

Good luck in your design!

Thanks! I'm planning to do my counters almost flush to the edge of the cabinets. I anned them at abt 25" and that was included in the estimate. But what I didn't include was fridge handles that stick out like 2". Do I need to account for that also?
The other 2 sides of my island will have 44" (sink wall to island drawers) and 47.5" (stool side of island).