Help with assaults

[phoenix]

Starting to play PB again. Been out for a while with other stuff. Sorry, but this is a kind of beginner post. 

Can anyone point me to a guide (or summarize briefly now?) where there is advice on how best to conduct assaults on fortified/entrenched positions. I'm playing Epsom 1, but it applies to so many other scenarios, of course. I mean, what exactly is the best way to do it, given a great mix of assets? 

So, for example, take an entrenched hex manned by PGs and AT guns. I have, say, 20 odd tanks and a Bn of infantry at my disposal, plus arty and air. What is the best way? These questions occur to me: 
1. Break down all my units or keep them at co level? 
2. Stack as many as possible in adjacent hexes - or at longest stand-off range possible, or somewhere inbetween? 
3. Mix stacks of tanks and infantry, or keep separate? 
4. Break down enemy with ranged fire (including prelim arty barrages and air attacks [the turn before, in the case of air]), or assault immediately? Do not assault until enemy units disrupted?
5. If assaulting immediately, or after disruption, assault a little at a time (tanks first in a stack, or infantry, then next counter down etc, to give as many attacks as possible) or just double click stacks and attack all at once. This question applies to ranged firing also - all at once or individual counters at a time? Or some ranged fire, some assault? 

Many more questions and options spring to mind, but that will do for now. 

Thanks for any help. 

Peter