After reading the posts had to immediately get the Mew Gull book and indeed, what an amazing story!
One thing struck me with 1930's record breaking aircraft how little they seemed to care about ensuring a good view out, especially forward (see Mew Gull or indeed Lindbergh's Spirit of Louis which had an even more limited view).
Did lowering the canopy so much really make a massive difference to the top speed of the Mew Gull? It seems it certainly gave him a lot of problems on the rough and ready rock-strewn strips in Africa as he had to just take off on the gyro compass and chance disaster a lot of the time!