Each block can have its own list of files to be deployed and ultimately all the purple commands are added to the MSI tables? If that's right then do you have to take precautions to ensure that one block does not run into another? By that I mean where the MSI code flow drops out of one block and then into another without branching around the latter. Would each block therefore be created with an apply statement or do you just funnel all of them into the same apply statement and IA takes care of the finer details when you build the media?
There's no project sample that shows how the blocks inter-relate in the project so I'm going to look at creating one with a little help from you good folk. I don't know however how I'd test it. Our firewall at work won't let me deploy anything externally and at home, all I've got is a typical internet connection with no access to any repository or other web space. So, if I can test then I suppose it all has to be local to my machine and neither do I have IIS installed so maybe 127.0.0.1 is the best I'm going to have access to.
I've got no axe to grind with 127.0.0.1 because there's no place like home.
I'd appreciate any help or clarification about what my options.

