As for the surface issues, here is Fisher in A Terrible Splendor
In late June 1934 Cramm, the new French champion, was in London playing Wimbledon. He was determined one day to conquer this tennis Everest, although the English grass courts really didn't suit his game. He had molded his strokes on red-clay courts, similar to those of Roland Garros. Clay-court specialists, used to a slower and surer bounce, developed longer strokes, enabling them to generate more power and topspin for the sluggish environment. But on grass the ball skidded low and quick and often erratically, so one needed a short backswing in order to react. "My backswing is too pronounced for grass," Cramm admitted. "Moreover, grass takes half the effect from a high-kicking service favored by many [clay-]court players like myself."
All this might help explain why he could lose in straights to Perry at Wimbledon but beat him at Roland Garros.
But it also makes his 5-set performance against Budge, on Wimbledon's grass, all the more impressive.