A "wait block" is an unintended wait caused by trigger conflicts, but I think you want to cause intended waits without literal "wait" actions.
The way I always do it is with death count timers. With DCs, all you need to know is that there are roughly 12 trigger cycles every second. In order to use this as a timer, you just multiply the number of seconds you want to wait by 12, and count that many trigger cycles using death counts.
Let's say you wanted a trigger to run, then wait 5 seconds, then a second trigger to run.
A simple way to do this would be to put "Set death count of Cantina to 62 for Current player" at the end of the first trigger. (The reason I use Cantina here is because it's an unused unit, so you don't have to worry about one dying during the game. I like to use units that are relevant to their purpose though, so if you are using Devourers for your mobile grid, you may consider using them for the mobile grid death count timer as well.)
The reason I made it 62 is because 5 seconds multiplied by 12 is 60. I added 1 because the next trigger is going to immediately subtract 1 from it. I added another 1 because the last trigger detects when it reaches 1, not 0 (just personal preference, I find it easier this way). You can rearrange the triggers to not need to add extra death counts but there's no reason to do so (although I often do anyways).
The wait trigger will be something like
None specified.
Current player has suffered at least 2 deaths of Cantina.Subtract 1 death count of Cantina for Current player.Preserve trigger.Then the last trigger (the one you wanted to run after 5 seconds) should have the condition "Current player has suffered exactly 1 death of Cantina." This will result in the trigger running 5 seconds (or 60 trigger cycles) after the first trigger.
You can include the action "Set death count of Cantina to 0 for Current player" in this trigger if you have a preserve trigger in the actions as well. That basically turns the timer off. If you wanted it to continually run, you could set it to 61 here instead (assuming the "subtract 1" trigger comes before it in the trigger cycle so it won't auto-delete a death count afterwards), that will make the trigger keep looping every 5 seconds assuming no other triggers alter the death count.
That's a basic outline of what I think you're trying to do. If I misunderstood anything or you need additional help, just reply saying so.
Edit: Wow, a lot of posts since I started writing this one