Personally, I go as heavy in tippet size as I can, if I am still correctly presenting the fly. Water clarity, current speed, size fish, depth of presentation, weight of the fly and how it turns over all determines the tippet to hook size.

Tippet Size to Hook Size
Tippet is the final section of line connected to the leader. Use the proper tippet size to enable proper turnover of the fly. Using a small fly with a heavy tippet will ruin a delicate presentation. Using a light tippet with a heavy fly prevents proper turnover on the forward cast and will result in a horrible tangle. (Info from Mike’s Catch Report)
Tippet Size
———-Hook Size
05x…………………….5/0, 4/0, 3/0, 2/0
04x…………………….3/0, 2/0, 1/0, 2, 4
03x…………………….1/0, 2, 4
02x…………………….1/0, 2, 4, 6, 8
01x…………………….1/0, 2, 4, 6, 8, 12
0x………………………2, 4, 6
1x………………………4, 6, 8
2x………………………6, 8, 10
3x………………………10, 12, 14
4x………………………12, 14, 16
5x………………………14, 16, 18, 20
6x………………………16, 18, 20, 22, 24
7x………………………18, 20, 22, 24, 26, 28
8x………………………22, 24, 26, 28

From AussieFly

Tippet to Hook size & Pound test table

This enables you to turn over your flies correctly, smoothly.

Tippet size
Diameter
Pound test
Fly hook size
0x
.011
15lb
2 – 1/0
1x
.010
12lb
1 – 6
2x
.009
9.5lb
2 – 8
3x
.008
8.0lb
4 – 10
4x
.007
6.5lb
6 – 12
5x
.006
5.5lb
8 – 14
6x
.005
3.5lb
10 – 18
7x
.004
2.5lb
14 – 24
8x
.003
1.0lb
18 – 28