Be carefull using the cheap types of easy outs etc. They are usually made in China etc and are not as strong as USSA ones. However if they do break you will be removing the engine to have it removed (EDM) Good blacksmith can drill that thing down the middle and then he will just pick out the threads. Not me, takes a reeeeeal steady hand.
Another word of caution two of those bolt are in direct line with the cylinders and if you go too far you can crack or possibly drill into a cylinder and thats a big WHOOPS
Had a customer we machined his block. He went and threaded a long water pump bolt in and cracked the cylinder. Luckily he saw it and we were able to sleeve it and save the newly machined block.