Tax Fields in Events and application of tax in custom fields and Price fields

At our site we have discovered a few issues which are causing problems

1st Problem : Application of Tax If you need to apply a tax to an event ie VAT or Sales Tax, You have to set the tax amount at the individual event level, you cannot apply is globally or at the category level. This is a real problem for us. The one good thing is if you create child events from a parent event, the tax rate is automatically populated. both for recurring events and events using additional dates plugin.

2nd Problem: : Tax Applied to all custom fields If you create a custom fee field, (ie the cost of equipment of say food at the event) and you have set a tax percentage then the the tax on these items is applied. in our case we have a 'Deposit fee' This fee is not subject to tax and we refund the fee if certain conditions are met. So we don't want tax to be applied, However with the current system if you have a Tax percentage in your event, tax is applied to all custom fee fields.

3rd Problem : Price does not include tax Most organisations (in Europe certainly ) quote their prices inclusive of tax. The amount in the price field is net of tax. So the price shown on the Event to the public is without tax which is misleading to most people. You can do a manual adjustment Price+ x% Tax and place the result in the Price Text Field. But every time your create an event you have to manually calculate the tax.

Required Solutions
Problem 1 -
1) Allow Tax rate to be Set Globally, so all events would have tax rate applied to the prices
2) Allow Tax Rate to be set at Category Level, overriding any settings at Global level for events in this category
3) Allow Tax Rate to be set at Event Level, overriding any settings at Global level and category level for this event and any child events

Problem 2
Have a new setting for custom fee fields Tax Exempt = Yes/NO. This would allow you to add Tax or not to a custom fee field.

Problem 3
If the tax rate is greater than zero recalculate the Price field to include the tax percentage.

NOTE: I have already raised these problems with Tuan. in respect to problem 2 , he stated "It would not be in the near future. I actually tried it, but failed because it's quite difficult to implement it (due to complicated fee/tax calculation support in the extension)"