It's difficult to gave a precise answer not knowing what is the purpose but let's try:
You could bunch more variable to create a more accurate proportion for your needs. Like:

• 0.5 to Steem activity (to ensure that the user is using steemit and reward users for it) - here it will be included the post average, comment average and resteem
• 0.25 to author rewards (it will reward people that are engaged with the community)
• 0.25 to steem power (it will reward people that hold steem and increase it's value)

But depends on your objective

keep steeming!