[UsIreland]

My personal preference is to start the average stack with about 75-100bb. To do that the big blind has to be about 100 or 150. So here's my suggestion:
Round-Small-Big
1 - 75-150
2 - 100 - 200
3 - 150 - 300
4 - 200 - 400
5 - 300 - 600
6 - 400 - 800
7 - 500 - 1000
8 - 600 - 1200
9 - 800 - 1600
10 - 1000 - 2000
11 - 1500 - 3000
12 - 2000 - 4000
13 - 3000 - 6000
14 - 4000 - 8000
15 - 5000 - 10000
16 - 6000 - 12000
17 - 8000 - 16000
18 - 10000 - 20000

With 25min blinds it should end right around the 6hr mark.

If you really dont watn to use 25's then i suggest:
Round - Small - Big
1 - 100 - 200
2 - 200 - 300
3 - 200 - 400
4 - 300 - 600
5 - 400 - 800
6 - 500 - 1000
7 - 600 - 1200
8 - 800 - 1600
9 - 1000 - 2000
10 - 1500 - 3000
11 - 2000 - 4000
12 - 3000 - 6000
13 - 4000 - 8000
14 - 5000 - 10000
15 - 6000 - 12000
16 - 8000 - 16000
18 - 10000 - 20000

Again with 25min rounds.

I hope this helps, also please note that the general rule of thumb is the tournament will end when 4% of the chips in play are in the blinds, so I suggest the tournament will end at around the 6000-12000 level or the 8000-16000 level.

I hope this is useful
Regards
Ian