Hi, a question about little greene paint. I am painting six chairs ( 3 different colours, 2 of each). I have decided to use the traditional oil egg shell, but the website says I need to use certain colour undercoat for each colour.. This is going to work out very expensive! Any ideas if I could use a little greene primer but a universal colour to do all the chairs?! I have chosen quite dark colours, yellow mustard, grey, dark navy or a rusty red. 