This weekend I ground down some previous welds and cleaned the engine side of the firewall where I am welding.  I worked on my technique for filling in the pinholes and gaps from where I removed the firewall brackets.  Finally got it down, but there is much more welding and grinding ahead.  Basically, I am filling in the spaces with a bunch of tacks allowing the metal to cool between tacks – slow and tedious, but it is working!  No pictures to share for now – maybe next weekend.