Melee and Firing questions

Sadly, I have a lot of time on my hands at the moment, so a number of questions have arisen from solo gaming. Thanks for any answers that can be given.

Melee:
A large unit makes its cohesion test on the VBU of the front unit. Does a large unit also use the VBU of the front unit when fighting a melee, even when the rear unit has permanent losses?

When the rear rank unit of a large unit routs in melee, and excess permanent losses remain, should they be applied to the front rank unit?

Are units allowed to withdraw voluntarily from a melee, or do units always have to continue in melee until one side retreats or routs?

Firing:
Are pila a one-shot weapon - that is, is the pila and PBWs rule only be applied once per unit per game?

I would suggest composite bows are under-effective, particularly at long range. At long range they are much less effective than slings, for example. My impression was that composite bows were longer ranged than short bows.

Movement:
Would it be fair to treat light and heavy war chariots the same as light and heavy cavalry for charge move bonus, charge speed and for pursuit? Where the rules say 'mounted', does that always include chariots?

Thank you again for any answers.

Hi Keith
         Like you I have a lot free or time as we are in lock down here in NZ for 2 more weeks. I haven't played BI for awhile as I mainly play full Impetus now, but here is my take on some of your questions.
1. Yes the Front rank is used for fighting and Cohesion tests. So you would get full Impetus bonus for charging even if the rear rank has loses.
2. Yes
3.Disengaging from combat is only in the full rules not in BI as far as I can tell.
4. yup pilum are a 1 shoot wonder

hope that helps

Very helpful indeed - it's very kind of you to reply so quickly.

What do you think about the composite bows thing? I'm considering tweaking the firing table to make composite bows a bit more effective.