for swiss, you can forget about discount. Its the [Birthplace] of all swiss made watches.
for vat refund, depends on whether the shop is able to do it for you on your behalf or you need to do it on your own.
Plus, if a shop is "tax-free" or "VAT-free", there will be a sticker on the main entrance door or a display at the payment counter, sometimes in their own language.
for discounts, the range can be from none to 30%, depending on the model you wanna buy, how much the AD Manager wants to give and also how much the SA is willing to offer you. and also whether that AD is having some sort of "sales" going on...
through emails, answers are rather standard, especially when you are not their regular clients. therefore the amount of discount offered to you is usually bare minimal.
bargain with them when you are in the shop and offer to pay them in full cash.
also, don't be surprised if you don't get any further discounts at the end of the day even if you offered to pay in cash... because ultra rich Chinese people are spoiling the overseas retail market EVERYWHERE.