Not much more to add code to, just float values of the current code to add visual representation to planets.
As your float value is set for metal have it adjust the sphere size of the planets to match or use a multiplier.

60% metal, 20% Life, 100% Gas

example: Metal count is 60%, adjust the visual the players seen on there client, set planet_core = $metal +(Core X 60%)

For gas value you could just expand the size of the atmosphere with the planet in the middle. While taking in account for the size of the metal.

example: set planet_atmosphere = ($metal + 100%)xGas

ok all this hurts me head its my day off im not payed to think.
but anyway the end result would be if you have a planet with 100% gas and 50 metal the planet would seem 50% larger than default, and the gas would double that size, making it a gas giant.

As for life there is no visual interpretation I can think of. And its ignorant to think all life is at the state we are, and add its visual representation as how bright of lights on the surface. So this one id leave to you.

Next perhaps we can have skins on the planets that change per area of percentages.