Of course, there is no hard and fast mandate that you need to include any Cp past the initial three you receive because you are battle forged. Your army could use only the patrol detachments and other detachments that do not issue Cp bonus's, that is entirely up the the individual and the Army they design and play. I intend to focus my rambles on my army of Flame Wolves for this article.
First I think that 6-7 Cp is about the most that I can squeeze into my army design process. Currently I seem to be taking a Battalion detachment (+3Cp), and either a Vanguard/Outrider/ Spearhead detachment (+1Cp) and occasionally a Auxiliary support detachment (-1Cp). These detachment choices for my Flame Wolves seem to be my optimal setup, I do not currently use any Lord of War choices or fortifications.
The next thought I am trying to think through is the uses of the Cp themselves. I always use a Cp to re-roll the seize roll so that I can go first, that reduces my allowance to 5-6 Cp, and the remainder I uses for critical re-rolls in game.
Is this the best use of my Cp?
To be honest I do not believe that it is. My play style, experiences and usage of Cp will become better the more I play, with the new Space marine Stratagems and Chapter tactics from the Space Marine codex there are new better ways to meaningful spend the Cp's besides re-rolls.
With this in mind I think the Salamander chapter tactics suit my play style and the fluff of my marines the best.
Whilst this does not help vehicles at all, it will go some way to reduce my reliance on Cp re rolls.
Okay the next stage of reducing reliance on Cp uses for re-rolls, is of course including units that passively buff the army. Some of these are Captains, Lieutenants and others. I think that I will leave for thoughts on army design to another article, when I feel the urge to put my thoughts down.
Anyway I know this is a somewhat inconclusive end, so let me just finish with, If you design your army to maximise Cp generation, always address what you seem to use your Cp for and see if there is a better way to gain that ability.