When it comes to using concrete nails, I really think that putting them in place with a nail driver is your best option. Though hammering them manually can be done, it is time-consuming, hard work. The force of the hammer on the concrete nails might also cause the concrete around them to crack or chip, which could result in you having to replace some of your concrete blocks.
Manufacturers make many types of nail drivers, so you should be able to find one that will fit into your budget. Think of it this way: the money you spend will be less than the cost of repairs if you run into problems hammering your concrete nails.