WANTED: Pond paint

Hi, im currently in the process of building my pond (2 years progress ) im struggling to find someone to fibreglass my pond so wanting to see input on what pond paint is like? Checked with bradshaws and they stock G4 or if theres a better quality product please let me know! Cant use BWL due to bottom drain, viewing window and skimmer/return! Also if anyone has any comments on Impermax ? Thanks in advance