Ok, that sounds like all the same problem.
Just for kicks, raise your idle AFR target to 14.0 and your cruise to 13.6. Those are richer than you want long term but will see if it helps your issues.
The problem is that below 1.5mS, the injectors become extremely non-linear and flow little to no fuel. With as large as the injectors are, it can't/won't meter the fuel properly at those rates.
If raising the AFR fixes the issue, that tells you the minimum pulse width is your problem. From there, you have two choices: run it rich and burn more fuel or swap out the injectors to smaller ones. Holley has 80# injectors that are physicallly identical, or you can get smaller ones in the same form factor from other vendors.
