to Solidar economics:
Why not make it that way:
Give 2 coins basic income per person that registers
Give up to another 8 coins. 1 coin for each x (100) coins the person has.
This way you have a incentive to hold some Solidar, if you hold too much still the demurrage eats it up, therefore you could lend them out to others so that they get their full universal dividend.