I hope the following helps:

it's easy to get caught up in intellectualizing all of this stuff when it is quite simple. any sort of power sounds (carrying chest voice higher, belting, screaming etc) will be loud.

the best advice i can give is this: know what sound you want for your particular music. if you know what sound you want then you can easily gauge how far off the mark you are with your voice.

but in general volume i think comes down to 2 things:

1. stylistic choice (how loud you WANT it)
2. how much volume you need to actually make the sound

staying in chest voice higher up typically requires more volume, if you lower the volume it typically means you would be bridging into head voice earlier. i prefer to call this how much you LEAN INTO the sound or not (because this is how it feels to me).

so i recommend asking yourself how loud you want to be (how hard do you want to sing or how soft do you want to sing), and then asking yourself how loud you need to be to scream correctly.

thinking about volume is really only necessary in an acoustic area without a microphone, because soft vocal parts may not be heard so you may need to adjust these vocal lines into a fuller voice so that it has enough volume to cut through the acoustic instruments. with a mic you can record soft falsetto parts in songs that can easily be heard when they are mixed correctly into the song etc.

Hey Phill Thanks for the reply :D

Like a lot of things I'm probably over thinking a bit
Just practice and have fun. Its probably a bit early in my voice training where I should even be messing around with more extreme effects, I still have a ways to go just with just my singing.

Thanks again for the help
"D"

Phil - On the money. Exactly how I look at the volume paradigm.

As long as you support correctly it doesn't matter. You can still sing higher with less volume as well. If it hurts, you're doing something wrong.