Set SharePoint permission on a folder using SPQuery \ CAML

I need to set permissions on a lot of SharePoint folders in a document library but I don't want to have to spin through all folders to find the specific one each time.  I have to set permissions on about 1000 folders and have an XML document where I'm getting the folders and their permissions from.  

I have the script about 90% written using a CAML query to get the specific folder.   (This works fine and returns the specific folder I'm looking for)

        $spQuery = New-Object Microsoft.SharePoint.SPQuery
	 	$spQuery.Query =	"<OrderBy>
								<FieldRef Name=BaseName Ascending=TRUE></FieldRef>
							</OrderBy>
							<Where>
								<And>
								    <Eq><FieldRef Name=ContentType/><Value Type=Text>Folder</Value></Eq>
								    <Eq><FieldRef Name=BaseName/><Value Type=Text>$folderName</Value></Eq>
								</And>
							</Where>"
		$spQuery.ViewAttributes = "Scope=RecursiveAll"
		
        $spListItems = $spList.GetItems($spQuery)
		

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However, when I try to set the $currentFolder, it is an SPFolder instead of SPItem.

			foreach ($spListItem in $spListItems)
            {
			
				$currentItem = $spListItem.Name
				$folderName = $spListItem.Folder.URL
				$folderName = $folderName.Replace($currentItem,"")
								
				$RelativeFolderURL = $spListItem.URL
				$currentFolder =$SPWeb.GetFolder($RelativeFolderURL)
				
			GrantGroupPermission $currentFolder
			}

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And the method to break inheritance and set permissions is only available on an SPItem object

  function GrantGroupPermission($groupName)
  {
   [Microsoft.SharePoint.SPGroupCollection]$spgroups = $web.SiteGroups
   [Microsoft.SharePoint.SPGroup]$spgroup = $spgroups[$groupName]
   $sproleass=new-object Microsoft.SharePoint.SPRoleAssignment([Microsoft.SharePoint.SPPrincipal]$spgroup)
[b][u]#The Next Line Breaks[/u][/b]
   $folder.BreakRoleInheritance("true")
   $sproleass.RoleDefinitionBindings.Add($web.RoleDefinitions["Contribute"])
[b][u]#This Line Doesn't Work Either[/u][/b]
   $folder.RoleAssignments.Add($sproleass);
   Write-Host "Permission provided for group ", $groupName
  }

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I've attached 2 files.  
One that works when I explicitly give it a folder name.
The second is my script that I'm trying to use CAML to get the folder name

I'm hoping someone here will be able to help figure this out.
WorkingAddPermissions.txt
SetPermissions.txt