"High-end" is too China-English...
(Do you mean 高端?)
I will suggest you use "High class" to describe in this sentence.
Let me translate into traditional Chinese which used commonly in Taiwan.
1) Slim Fit 合身版
2) Regular Fit 普通版
3) Short, Regular, and Long (this is referring to suit jacket length) 短版,普通版,長版
4) What size suit do you wear? 你(您)穿甚麼尺寸
5) Would you like me to get your measurements? 你(您)介意讓我知道你(您)的尺寸嗎?
6) 100% wool suit 百分之百羊毛
7) Would you like to try this one on? 你(您)想試穿這件嗎?
8) Does it fit good? 這件合身嗎?
9) Is this suit for business? 這是上班穿的套裝嗎?
10) What kind of event is this suit for? 這件套裝適合甚麼樣的活動?
11) What size sweater do you wear? 你(您)穿甚麼尺寸的毛衣?
ps.你and您 both mean "you" ,but 您 is politer.
Good luck !