Hi USN_Sam.
I, like hunt4fun, use slugs in my shot gun. I use as Mossberg 500. Here is a list of recommended choke tubes based on shot size from Mossberg's website.
MOSSBERG RECOMMENDED CHOKE & LOAD USAGE CHART
GAME
GAUGE/BORE
DISTANCE
CHOKE
SHOT SIZE
QUAIL
WOODCOCK
12 & 20
12 & 20
15-30 YDS.
30+ YDS.
SK/IC/M
IC/M
#7 1/2, 8, 9
#7 1/2, 8
DOVE
12 & 20
12 & 20
20-30 YDS.
30+ YDS.
IC/M
IC/M
#7 1/2, 8, 9
#7 1/2, 8
PHEASANT
GROUSE
12 & 20
12
20-30 YDS.
30+ YDS.
IC/M
M/F
#5, 6, 7 1/2
#4, 5, 6
TURKEY
12 & 20
12
15-30 YDS.
30+ YDS.
TURKEY
TURKEY
#4, 5, 6
#4. 5, 6
RABBIT
12, 20 & .410
12 & 20
15-30 YDS.
30+ YDS.
IC/M
IC/M
#5, 6, 7 1/2
#4, 5, 6
SQUIRREL
12, 20 & .410
12 & 20
15-30 YDS.
30+ YDS.
IC/M/F
IC/M/F
#4, 5, 6, 7 1/2
#4, 5, 6
LARGE DUCKS
(MALLARD, PINTAIL)
12 & 20
12
15-30 YDS.
30+ YDS.
IC/M
IC/M/F
#3, 4, 6
#3, 4
SMALL DUCKS
(TEAL, BUFFLEHEAD)
12 & 20
12 & 20
20-30 YDS.
30+ YDS.
IC/M
M/F
T, BBB, BB #1
T, BBB, BB
LARGE GEESE
(GIANT, WESTERN CANADA)
12
12
20-30 YDS.
30+ YDS.
IC/M
M/F/XF
T, BBB, BB #1
T, BBB, BB
MEDIUM GEESE
(SNOW, LESSER CANADA)
12
12
20-30 YDS.
30+ YDS.
IC/M
M/F
BBB, BB, #1
BBB, BB
IMPORTANT NOTES: Choke & shot size selection will vary depending on target distance and hunting conditions.
SK: Skeet
IC: Improved Cylinder
M: Modified
F: Full
XF: Extra Full
Additionally, after a Google search of 00 buck shot, I found a several sites that recommend the modified choke.