How much fit allowance in shirt body?

[couch]

I'm correcting measurements for a second trial shirt from Jantzen. The shoulder peak-to-peak and chest measurements I provided for the first one were off by enough that I'm not sure whether to specify "medium" (6-8 inches) or "form-fitting" (4-6 inches) of fit allowance in the body with new one. I know this is in part a question of personal preference, but I'm wondering what makers and more experienced consumers here find a good allowance for wear under a business suit (and which will frequently be seen at the office without jacket). I like fit that looks neat but correct, not so tight as to restrict movement or look like an ice dancer. Since proportions may matter, corrected sizes will be shoulder: 18 in, chest 38.5 in, waist 30.5 in. I'm thinking of asking for 6 in allowance. What do you use? Thanks for all opinions.

[AlexanderKabbaz]

For from Size 14.5 (Neck) to Size 16.5, the standard amount of (shrunk) fullness is as follows:

Chest-Waist-Hips

Fitted Shirt: 5-4-5
Normal Shirt: 6-5-6
Full Shirt: 7-6-7
Roomy Shirt: 8-7-8

Standard Neck-Chest sizing is as follows:
Neck - Chest
13.5 - 32
14 - 34
14.5 - 36
15 - 38
15.5 - 40
16 - 42
16.5 - 44
17 - 46
17.5 - 48
18 - 50

EDIT: All the above measurements are inches. Sorry for the omission.

[couch]

Alex, this is perfect. Thank you!

Looking at your standard neck-chest chart, I see why most RTW shirts billow on me, with a 15.5 neck and 34.5 sleeves (and other dimensions as above).

- Randall