IMO, the basic strategy for a cash set, regardless of size, is the following three steps:
1 - Get just enough of the smallest denomination to make things run smoothly. In this case that's 100 x 25¢.
2 - Get enough high denomination chips to more than cover all possible buy-ins and re-buys. I would say 60 x $25 and 40 x $100 but ymmv (your mileage may vary).
3 - Fill up the rest of your set with the "workhorse" chip. Depending on stakes, this could be a $1, $5 or even higher. For your stakes, either the $1 or $5 is your workhorse, so I would roughly get equal numbers of each.
Following the above rules, a 600 chip set for 25¢/50¢ or 50¢/$1 is
25¢ x 100
$1 x 200
$5 x 200
$25 x 60
$100 x 40
Or pretty much what has been said already....
L
PS note that the rules apply when you are trying to limit the number of chips you need to buy. I'm not really sure I even grasp that concept. If that's not the case, just buy a sh!t-ton of everything.