I look at some of the proposed thermosiphon piping and wonder where in the world these ideas came from. A fluid thermosiphon works by the fluids density decrease when it is heated. The less dense fluid will rise and flow to the highest point. When it cools, it falls to the lowest point. The pressure force created is small so every effort should be made to reduce piping friction and temperature loss. When using a regular domestic hot water heater as a storage tank the supply from the stove coil should enter the top of the tank in an unobstructed tapping. Usually the only one present is the PRV tapping. You can't use the cold water inlet because it has a dip tube. You don't want to use the hot output because when you turn on the hot water, the house water pressure causes flow out of the tank stopping the thermosiphon action. Removing the PRV from it's own tapping will violate the plumbing code. But, before water heaters had tappings for the PRV only, the PRV was installed in the straight end of a tee mounted with a close nipple in the tank's output. Pipe the stove coils supply side to the previous PRV tapping. Hot water supply is taken from the side port of the tee that now mounts the PRV. Be sure to use a long temperature sensor PRV. You want it to reach into the tank water if possible. Insulate around the tee. The object is to reduce heat loss so the PRV sees the tanks water temperature.
The return to the stove coil should come from the tanks bottom drain tapping. Remove the boiler drain and replace with a tee. The side port of the tee should go to the stove coil return. The boiler drain should go in the straight through port of the tee.
Remember the thermosiphon force is small, so use smooth wall pipe, i.e. copper to minimize viscous friction. Consider using a larger pipe size, 3/4" or larger. Use long sweep 90 deg el's. Consider using a pair of 45 deg els to turn a corner. Do anything to reduce pipe length and internal flow restrictions. Insulate the hot supply line between the stove coil and the tank.
Pipe the rest of the storage tank as you would normally. Backflow dual check on the cold inlet, bladder tank, etc. if required by your local plumbing code.