B2 specifying toolsets and options

I'm uncertain about providing options for various configurations.

If I have a user-config.jam that has specifications for toolset of gcc, msvc,
and 

Clang AND clang-win

And more than one version of Clang, say 8.0.0 and 7.1.0

And I am specifying various options.

Can/should I use <toolset>clang-win

Like this

<toolset>clang-win:<cxxflags>/std\:c++17

<toolset>clang:<cxxflags>-std=c++17

To obtain the different specification formats, one MSVC and the other Clang
style

Will 

<toolset>clang:<cxxflags>-v apply to both clang-win and clang?

Can I also fully qualify with compiler version to provide different options for
different versions? 

For example

<toolset>clang-win-7.0.1: :<cxxflags>/std\:c++14
<toolset>clang-win-8.0.0: :<cxxflags>/std\:c++latest

Thanks

Paul

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