How to set the value of a Fixed amount Commerce Coupon using Rules?
After much digging, i was able to resolve this using a rules component. The trick is, after generating your coupon code using rules, that is, 


  event: completing the checkout process
  
  condition: your condition (e.g order contains a particular product
  etc)
  
  action: create new entity => commerce coupon action: set data value
  (do this for the coupon code, max number of uses, coupon type (human
  readable name), etc) action: save entity => (your created entity)
  
  action: create new entity => commerce line item => commerce coupon
  (set your values) action: save entity => (your newly created coupon
  line item)
  
  create component:
  
  component plugin: rule name: name your component here (e.g "set gift
  coupon value") data type: commerce coupon label: (give a label that
  you can identify it easily with) machine name: (give a machine name
  that you can identify easily) save component.
  
  Under conditions: entity has field: (identify your coupon fixed amount
  field here e.g "coupon-fixed-value-component") action: set a data
  value => (here you identify the fixed amount coupon field and then set
  the value you want)   save component
  
  Come back to your earlier created rule, 
  
  add loop: (it should automatically capture that you want to loop into
  the commerce line items e.g "commerce-order:commerce-list-item"  save
  loop inside the loop, add action = > (here you'll select the component
  you created, it should automatically detect that you want to fire this
  component on your created coupon entity initially created within this
  rule e.g "entity-created" save the action.
  
  perform any other action if you want, like send email to referenced
  user in the gift card.
  
  That would do. each time you complete the checkout for the product
  referenced in the rules condition, a gift coupon will be created and
  the amount would be set based on your rules component action value.
  
  Limitation: You have to do this whole process for every different
  amount of gift coupon you create.
  
  Possible improvement: Allow a user to specify the amount at product
  creation time, then use rules to capture this amount and then set the
  coupon value based on the set amount of the product
  
  More improvements welcome..