While this isn't in the same ballpark as a quality ASNU machine & isn't a substitution for a guy like Trav's services, But.....As you know I did a lot of LSx conversions & stuck injectors are very common with used "pullout" engines. Here's what use.....
You will need a Pressure Vessel/Pot. My first inneration used a Paint Pressure Pot, But it was only rated at 50 psi which didn't allow me to bump the pressure. My Snap-on dealer had this pressure pot on his truck for over a year before selling it for half price on a cash deal.
It will need a regulator, A shut off valve on the outlet, And a pressure gauge downstream of the shut off valve.
A pressure gauge at the regulator is nice but not really needed.
You will need a good supply of dry filtered shop air (I know you have this), You don't want water or debris getting in your vessel!!
I use a OTC 3398 injector pulse generator, HERE
It comes with a EV1 injector connector.....I made a Multec 2 & EV6 splitter/jumper harness & will cover ALL GM port injectors, And most other domestic & asian injector connector types.
The 3398's output (timebase-Ms) is accurate enough to Balance Test injectors via the pressure drop, You pressure up the rail to X amount of pressure, Flip the shut off valve, And I do a 1-Pulse at 100 Ms & a 50-pulse at 10 Ms......Record the pressure drop. Repeat for each injector.
Of course....you need to unstick & flow the injectors before performing a balance test, I like a 50/50 mix of gasoline & GM top engine cleaner 19355198. Do not pour gas out of a gas can into the pressure pot! Either use a pump & filter to pump gas from the can OR (What I do)......Use a fuel injection pressure tester/gauge on my shop truck & bypass some of it's clean fuel into my pressure pot.
To unstick an injector....Bump the pressure up to @ 70 psi, Hit the coil with a 50-pulse & lightly tap the injector body with a screwdriver handle.
Amperage & Voltage waveforms/signatures can be monitored, But it's not easy to get an injector "hot" with the 3398 as it will time out when pushed hard.