Actualy you can create a topic here with all the basic info on the game you have on hands, then you can edit it if needed. This will ensure people see it and you don't need to do it in the game for now ^_^
And for idea 2) i had (in case you will use it sometime) - maybe you could set strict places for the towers right around the Core, 8 in total (and max possible for the auto play ability) and they will just be filled at the auto-start of the game. This will give ability to farm gold atleast and some other resourses at first (as futher buildings won't be protected by towers).
But i'd think % based gain of best run rewards is easier to implement.