I have a double right now (one large, one small) and I use the small one to drip dry anything that doesn't go in the dishwasher. It's convenient, but even so I'm planning to switch to a single large sink in the future. I haven't found any double sinks that I really like, but I will admit I haven't seen a great solution to drip drying pots and pans. I really do use that second sink a lot (even if I towel dry my pots, which I don't usually bother to do, I still have to have a place to put them until I've finished the dishes). Most dishracks I've seen are intended for plates and utensils, which I just put in the dishwasher. If I can find a good dishrack for pots and pans, then I will be very happy with a large single basin sink I think.

I only specify an overmount sink for clients if the benchtop surface warrants one. The last time I did was because the client wanted a timber benchtop. I managed to find a beautiful black quartz composite sink that worked well and looked like a feature in the kitchen because it matched the colour of the cabinets. My usual go to sink is definitely undermount because of its aesthetic and practical advantages. Small chips can always be smoothed out if need be but really, there is no substitute for being careful!

Congrats on doing the planning and thinking about how you will use the space, absolutely essential even if you don't do a lot of cooking. A well planned, functional kitchen will make your life easier and add value to your home. I am an avid cook and long time renovator so have done many kitchens in my time. Looking at your space and how I personally use a kitchen I'd suggest two sinks. A small prep sink on the stove side and a large double bowl sink on the island, with dishwasher underneath. I think your hotplates are in the right location as long as you have at least a 500mm or more of bench on the wall oven side and then ideally approx 2m (if you have it) from the hotplates to your prep sink. This divides your kitchen into zones, prep, cook on the back wall and clean up, serve on the front. If you tried to put everything on the back wall it would be too crowded and not work. Think about a desidng that allows for two people at all times to be in the kitchen, you do this by dividing your kitchen into zones. Prep, serve, clean up and think about how you entertain or liaise with the family whilst you are in the space. I hope this helps and best of luck with your new kitchen.

@wuff, Thank you so much, and congratulation for your renovation, I wish you will enjoy it for so many years to come. Yes, I agree living into a granny flat next to my son was my husband wish before he passed away. It is good to be close to family. Also I love the suburb which I have been lived in for 22 years. My Daughter and her family is living close by too. Most of my close friends are living around and we always gather for a brunch, or lunch or watch movies. The good thing is most of my friends pick me up and don't let me drive most of the time when we go out. Thank you again