but simple setting the hero level high consisnts in a bug: the heroes get stuck at level 5. They simply have an xp-gain rate of 0%...
there is a tabel in the gc that only has 5 values. the last one is '0' and it is something like 'Hero - Experience Table' or stuff liek that - dunno ahvenÄt doen that for qite some time ^^
if you use custom gc - take a good look into that table ^^ (simply set the last value >0 and they will continue to gain xp for eternity ^^)