If you’re going to buy a tourney set, I’d recommend a 600 chip set, so that it can handle both T20K single table tourneys and T10K 20-person tourneys. Might as well spend a little more on the front-end and future-proof the set.
The breakdown that I, and many others, consider to be an ideal breakdown for a very flexible 600 chip tournament set? It is ideally suited to a 20-player T10,000 tourney (one of the most popular starting stack sizes), with starting stacks of 8/8/4/7. There are plenty of T5000s and T25Ks for rebuys and color-ups:
160 x T25
160 x T100
80 x T500
140 x T1000
50 x T5000
10 x T25,000
(Or 60 x T5000 and no T25K)