The International Open Source Hydrogen On Demand Builders Network.
Map alone wont work. and a water for gas cell system wont do much for you. Water 4 gas systems are meant for experimentation more than anything. If you really want to get into this buy a good system.
The only advice I can give regarding your question is to avoid using the water4gas system. It is a scam and its inventor, Ozzie Freedom (not his real name but his alias) is a con man. There are excellent systems developed by a number of individuals. For instance, Hydrogen Garage sells the Bob Boyce system that truly works as advertised.
When boosting with hydrogen an efie is essential, otherwise the oxygen sensors will give a lean fuel reading and add more fuel to the mix, thereby nullifying any mileage gains. Without the efie your first fillup of gas will give you significant improvement in mileage. Your second fillup will give you less improvement, and your third will give you no improvement. The car's computer learns from the sensor inputs and adjusts accordingly. That's why an efie is necessary.
You can also buy a hydrogen volo chip from Hydrogen Garage which will prevent the problems created by the computer's original chip. Give Bro Andrew, owner of Hydrogen garage, a call and he can give you all the advice you need to optimize your boosting system.
Note that I'm not connected in any way with Hydrogen Garage nor do I get kickbacks for referring others to them. They're just an excellent single source for boosting components and for advice on getting the best out of your system.