Hi Degian. A 3-day event will be regarded by players as being a serious tournament, and players will want to bring their best game. It's really hard to play your best game when blinds are being increased by 50% or more in several increments such as you have between levels 3-4, 6-7, 12-13, 14-15, 20-21, and 22-23.
To remedy this I would recommend dropping your first level, 25-50. With an average chipstack of 20,000, a 50 bb is 400x the average stack, practically meaningless. A starting bb of 100 is still 200x the bb and allows for plenty of time to "get comfortable". The second change I'd recommend is decreasing your blind intervals from 60 mins to 45 or 50. Doing these two simple steps will allow you to remove the drastic blind increases and allow players to settle in and play their best poker, something serious players really appreciate.
With those changes, using a 45 min. interval and 45 min dinner break you can restructure day 1a-1b as:
50-100
75-150
100-200
125-250
150-300
200-400
250-500
300-600
350-700
400-800
500-1000
Day 2 as:
600-1200
800-1600
1000-2000
1200-2400
1500-3000
2000-4000
2500-5000
3000-6000
4000-8000
5000-10000
6000-12000
Going into the final day, the average stack (assuming 9 players), would be 27x the bb at 8000-16000 level.
8000-16000
10000-20000
12000-24000
15000-30000
17000-34000
20000-40000
25000-50000
30000-60000
35000-70000
40000-80000
50000-100000. At 50k-100k blinds, with 3 players remaining the average stack is 13x the bb, with 2 players it's 20x, so the end is very near if it hasn't already occured.
After level 1-2, the largest percent blind increase in the above structure is 33%, with the majority at 25% or less. Keep your antes at 10% or greater of the BB and you'll have a tournament without uncomfortably harsh blind increases.