I have recently been playing a lot of FFA and the supply you get from a kill is way overtuned. Even a 1 kill difference means you win / loose in the final 95% of the time, even with better play.
50 extra supplies is simply too much. 20/25/30 supplies would be way more fair. A 275 vs a 225 player is still very loopsided but not impossible compared to 350 to 250. And a 275 vs 250 match is almost even, with a slight edge to the player that got more eliminations.