edit - my apologies - I was leaving work and read your question to quickly - all of your eligible coins wil stake by default. You coins age will determine how many stake at any given time.


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as far as donations to the project from staking rewards....


The default is 5%....that is for every 100 stakes you receive five of them are donated.
A stake reward currently consists of 2.15~ xspec.
i personally have my wallet set for 50%.....so every other stake reward goes to support our devs and project.
I get one they get the next one.

You can adjust this in the wallet/client under options>staking donation
while there be sure your staking is enabled by the check mark in the box right above.

And Thank you for your support