Yeah you probably could get away with making the T500 your top chip for that starting stack, something like 8/8/6 of T25/100/500. But the rebuy point is important, you would need 8 chips for every anticipated rebuy, if you had T1000 available, you would only need half of that. If you played T5000 instead of T4000 starting stack, you could get away with one chip per rebuy.
Let's consider the math.
For simplicity, I will assume 10 players with an estimated 5 rebuys needed.
T4000 starting stacks with only T25/100/500
Starting Stacks 8/8/6 of T25/100/500 220 chips.
Plus 2 T500 chips per player for color ups (20 more T500)
Plus 8 T500 chips per anticipated rebuy (40 more T500)
Gives you a lean
280 chips .
T4000 starting stacks with T25/100/500/1000 chips
Starting Stacks of 8/8/4/1 of T25/100/500/1000 210 chips
Plus 1 T1000 chip per player for color ups (10 more T1000)
Plus 4 T1000 chips per player for anticipated Rebuys (20 more T1000)
A leaner
240 chips.
Now ordering quantity and whatnot will influence what you actually buy but the bigger denominations come in handy when you consider rebuys and color ups, even in single table tournaments. You can get away with high chips only for rebuys because the low chips needed are already on the table, and introducing only big chips on color-ups makes it easier to keep from adding chips to the game that will just be removed later.