Fast Search Refinement and Scope

Manage refiners and refiner settings (FAST Search Server 2010 for SharePoint)
http://technet.microsoft.com/en-us/library/gg193929.aspx
Set-FASTSearchMetadataManagedProperty -Name <Name> -RefinementEnabled <Flag>
To enable a managed property as shallow refiner by using Windows PowerShell
$mp = Get-FASTSearchMetadataManagedProperty –Name <ManagedProperty>
$refiner = $mp.GetRefinerConfiguration()
$refiner.RefinementType = “DeepRefinementDisabled”
$mp.SetRefinerConfiguration($refiner)
$refiner
Use Powershell to create site scope
Search scopes in FAST Search for SharePoint (Part 1)
http://blogs.msdn.com/b/jorgeni/archive/2010/02/26/search-scopes-in-fast-search-for-sharepoint-part-1.aspx
New-SPEnterpriseSearchQueryScope -SearchApplication "Search Service Application" -Name MySimpleScope -Description "My Simple Scope" -DisplayInAdminUI 1 -ExtendedSearchFilter ‘title:vista’
Specifying which fulltext index to search
FAST Search scope filters have one additional capability; you can in the filter specify which non-default fulltext index (=composite field if you’re familiar with FAST ESP terminology) you want to query. To specify the fulltext index as part of, or the whole scope filter use “FullTextIndex=” as part of the filter. Note that the you separate the FullTextIndex parameter and the value with equals (=).
New-SPEnterpriseSearchQueryScope -SearchApplication "Search Service Application" -Name MySimpleScope -Description "My Simple Scope" -DisplayInAdminUI 1 -ExtendedSearchFilter ‘title:vista,FullTextIndex= mycustomfulltextindex’

Fast Search Query Tool
http://fastforsharepoint.codeplex.com/