Wolfpow while you have the car stripped down to the PAN .. I would use “POR15” paint …Its chip proof and rust proof.. much better then any of the so called rust paints like rustolium.. Its available from http://www.eastwoodco.com
PinkMG mentioned my Metal trunk ..I had made a cardboard templete all taped together that fit perfect in the space under the hood and took it to a metal shop that fabricated for me ..Cost me $100.00
they cut sheet metal and welded it together..there s picture of it in my gallery