I would not call it "conservative tuning." Rather, the fuel and timing tables are adjusted for the bigger injector size.
The benefit of the big injectors is getting a big fuel shot in there quicker, while all other things remain the same.
If adjusted properly, the timing isn't any "lower" as the same amount is still injected BTDC. The injection event itself is simply shorter, and shorter is better.
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Not sure how you would not call it conservative tuning.... Some of what you are saying makes sense and the rest either doesn't or could be misinterpreted.
For simplification lets use some nice rounded numbers:
Let say we are trying to get 600 rwhp and that with stock injectors it takes about 3200 uS PW to get us there. That would mean that by 4000 RPM you would be injecting fuel for 76.8* of crank rotation. To get that long of a shot in there you are either going to run high timing to get as much in before TDC as possible, causing high cylinder pressures before TDC, which after a certain point hurts power and puts more stress on the motor; or you are going to be spraying a lot of it after TDC, chasing the piston down the bore with fire and raising EGTs. Either way it is a long heat cycle on the piston.
Now we'll take the same setup and run 100% over injectors, which should mean they are flow tested to flow double the fuel of stock injectors at the actual operating parameters. At full pressure it should take half the time to get the same amount of fuel out of the injector, so to get 600 rwhp we can now use a 1600 uS PW. Now we can get the same quantity of fuel into the motor in 38.4* of crank rotation at 4000 RPM. Now instead of building cylinder pressure so early, where it is fighting the motor, we can inject much closer to TDC; we can also stop injection not long after TDC.
Again for simplification if we used 50/50 timing at 4000 RPM you would be running 38.4* of timing to get half the fuel in before TDC on stock injectors - if you used 38.4* of timing on the 100% over injectors you would be putting all of your fuel in before TDC. If you used 17.3* of timing you would be at a 50/50. So for any given quantity of fuel you run less PW and in turn less timing on bigger injectors - which in my opinion is "more conservative tuning".
