Figuring out the breakdown is really just about how much playability you want to have, and that is defined by the multipliers, for NL/PL tourneys usually 2x or 3x. Using these simple multipliers you can figure out a suitable breakdown for any values you want to use. Take this common T10k tourney with a T25 base starting stack for example:

12x T25 (**3x **T100)

12x T100 (combined with T25’s **3x **T500)

7x T500 (T25/T100/T500 —> **5x **T1000)

5x T1000

That last jump’s multiplier is just way too big, and people generally tend to use too many T500’s. For a full table, going with a 2x multiplier for every step would be my minimum, and that should go up if playing short-handed. If you want great playability though, I would consider using 3x even for ten players.

You can of course use a mixed bag, and sometimes you compromise a little to end up with full racks without too many filler chips. For example if you want to use a 3x but only have very few chips of the highest denom in stacks, then a 2x for the last jump will work great. The first jump (2x instead of 3x) is another good spot to trim down the total amount of chips, as the moment of worse playability should be over relatively soon.

The starting stack listed in the OP, 10/8/6/1 (1k/5k/25k/100k) for 300k, uses a 2x multiplier from start to finish, so for 10 players it works fine with good enough playability. Add the color-ups (0/2/2/0) and you have a total of 290 chips, so room for 10x 100k I guess to actually make it a T400k set. For increased playability you could consider using a mixture of 3x/2x multipliers and start with 15/12/5/2 for T400k, plus color-ups (0/3/3/0), that comes to a set of 400 chips.