If you're sure that adding printers is slowing down your login script, than I suggest you use PriMapState(). I think you should not add printers that are installed. Checking this will speed up your script.
 Code:
;;;;;;;;;;;;;;;;;;
; Script Options ;
;;;;;;;;;;;;;;;;;;

If Not @LOGONMODE
	Break On
Else
	Break Off
EndIf
Dim $RC
$RC = SetOption("Explicit", "On")
$RC = SetOption("NoMacrosInStrings", "On")
$RC = SetOption("NoVarsInStrings", "On")
If @SCRIPTEXE = "KIX32.EXE"
	$RC = SetOption("WrapAtEOL", "On")
EndIf

;;;;;;;;;;;;;;;;;;;;;
; Declare variables ;
;;;;;;;;;;;;;;;;;;;;;

Dim $DefaultPrinter
Dim $Printer2

;;;;;;;;;;;;;;;;;;;;;;;;
; Initialize variables ;
;;;;;;;;;;;;;;;;;;;;;;;;

; Change the values to your needs
$DefaultPrinter = '\\YourServer\PrtAcc01'
$Printer2       = '\\YourServer\PrtAcc02'

;;;;;;;;
; Code ;
;;;;;;;;
If primapstate($Printer2) = ''
	AddPrinterConnection($Printer2)
EndIf
If PriMapState($DefaultPrinter) = ''
	$RC = AddPrinterConnection($DefaultPrinter)
EndIf
If primapstate($DefaultPrinter) = 1
	$RC = SetDefaultPrinter($DefaultPrinter)
EndIf

;;;;;;;;;;;;;;;;;;;;;;;;
; Personal UDF Section ;
;;;;;;;;;;;;;;;;;;;;;;;;

;;;;;;;;;;;;;;;
; UDF Section ;
;;;;;;;;;;;;;;;

; Add here the PriMapState() UDF