If we think back we can all remember going over leads with a damp scrim and little panes for that matter,we all new when we drove off that there might be the odd smear on them like you say especially this time of year,to get through loads of work your not gonna get them all spot on but that`s when a good relationship with the custie comes in,you want to be somewhere between mc`donalds and claridges and you won`t go far wrong,if you try and be a perfectionist your be dissapointed.