I generally tend to discourage dual-purpose sets, because of the monetary and security risks they pose to the cssh game.

You can easily build a decent playable 10-player cash set with 600 chips, and 400 tourney chips will more than adequately cover a single-table event.

To address your specific requirements:

Tournaments:

- 15-16player (2 tables of 8 or 3 of 5) would be the biggest the game would ever get. most likely it’ll just be 8-10 people
- Will probably use 25/100/500/1k/5k progression and so 5k-20k starting stacks. 8/8/4/7 is good with me, but more chips always better.
- Open to exploring the idea of a T100 base (does this make it easier for newer players?). Don’t think I’d use a BBA just because most players will be newer and these are just family tournaments

A 16-player T25-base tournament set covering T5K to T20K starting stacks (100bb-400bb) will require at least 475 chips, if using a 8/8/4/7/x breakdown with no re-buys:

128 x T25

128 x T100

64 x T500

112 x T1000

43 x T5000 (11x used for color-ups with 16 x T10K stacks or larger)

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475 chips minimum, which also allows for a single-table (10-players) tournament using T25K stacks (12/12/5/6/3). I'd round up to at least multiples of five (130/130/65/115/45), or 485 chips total. Rounding up to even 1/2-barrels is an even 500 chips (130/130/70/120/50), leaving 500 chips with which to build an 8-player single-table cash set.

For comparison, a 16-player T100-base tournament set covering T20K to T80K starting stacks (also 100bb-400bb) requires at least 448 chips if using a 10/4/7/x/x breakdown with no re-buys:

160 x T100

64 x T500

112 x T1000

75 x T5000 (11x used for color-ups with 16 x T20K stacks or larger)

37 x T25000

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448 chips minimum, which also allows for a single-table (10-players) tournament using T100K starting stacks (10/6/11/7/2). Again, I'd round up to at least multiples of five (160/65/115/75/40), or 455 chips total. Rounding to even barrels is 480 total chips (160/80/120/80/40), leaving 20 free chips to add to the cash set (or 30-35 cash chips if you keep the T500 count at 65 or 70 -- you really don't need 80 of 'em).

The T100-base option does free up some of your 1000 total chips for the cash set side, and both tourney options will basically play identically (although only 8x small denoms in theT25-base set will require more change-making that the 10x of the T100-base set).

Cash:

- For cash, will likely just be 1 table, and mostly mostly .05/.10, but may (1-2x per year) as big as .25/.25 or
*maybe* .25/.50. A $1000 bank would probably be more than enough.
- Would like to use a $20 chip, regardless of whether I keep a T25 in the tournament set.
- Even if unnecessary, I kinda want at least a barrel of $20s for the fun factor.

For cash sets, I typically recommend at least 600-chips (100/200/200/80/20) for a 10-player table. Scaling that to your 5c/10c single-table (8-player) game, you are looking at something along these lines:

80 x 5c

160 x 25c

160 x $1

80 x $5

20 x $20

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500 total chips, which equals a $1,004 bank, or roughly $125 per player (at 5c/10c with a $20/200BB buy-in, that is 6+ bullets per player). At 25c/50c with a $50/100BB buy-in, that is 2.5 bullets per player.

It wouldn't hurt any to add more $1s for the micro-stakes game, and adding extra $5 chips will be helpful for larger 25c/50c games -- but you can always allow $20 and/or $100 bills to play if your game gets too large for the set.

First figure out which tournament set you want to go with, and if it's less than 500 chips, then fill out the cash set with extra $1s and $5s to total 1000 chips in the combo set.