Let me see...
1/8" would translate into around 0.32". In 2010 the ShadowCat should have an approx ATA of 41.5 so your 1/8" does fit. Better have a slightly longer ATA than a slightly shorter one.
You could adjust your ATA by twisting stirng AND cables. Keep in mind to twist both as the Cam timing would change if you twist only one of those. In my mind 1/8" is nothing to worry about.
I wont worry about that 3/8" BH either. I never care about the BH on my bows as the BH is in a close relation to the Cam rotation. A slight different rotated Cam will produce a different BH. So twisting string OR cables will change your BH. But then this will change Cam timing, draw length and overall efficiency of the bow.
(2) Martin ShadowCat 2010