Lilac Sky

[Achebe]

Hi crimson - iambic heptameter + terza rima is an interesting combo. I'm not a big fan, but it's a worthwhile experiment.
Some sugguestions below

The brilliant sun sets deep against the darkened lilac sky ....'Brilliant sun' is hackneyed
Makes tearful eyes aglow, by beams, in sapphire-amber hue
It paints the deathly speckled lake tints mournful moods belie 

My feet are bare on wooden boards and careful not to skew
Still half my heart would long to sink beneath and breathless, burst ....don't follow the metaphor of half a heart being breathless
While half it longs to dash inside to simply breathe in you 

If half my heart were faithful hunger, half were faithful thirst
Then faith would leave me starve or parch, each way a steadfast end
I'd drown in joy or walk with pain, by each I would be cursed

I'd sell myself to see my life through your dry eyes, my friend
For faded bars you're blind to see that will not let me free .... Since it can't be 'my friend for faded bars'?, you mig or 'my friend, for faded bars you're blind to see - they will not set me free (not 'that'). What are 'faded bars' anyway?
I scream and shout and wail and cry, yet still they will not bend ....The metaphor doesn't work because the literal example of bars being bent by shouting and wailing, doesn't work. It might work if you said 'I push and thrust etc. .... they will not bend'

Still I'd remain, and happy too, if when you look to me
Against the lilac sky you see the free bird I might be