Instead of using viewWillAppear/viewDidAppear, just stick with viewDidLoad. I’m not seeing documentation about this yet, just that I had to use loadView and viewDidLoad to stop some crashing. My creation steps now look like this:

- (void) viewDidLoad
{
    [super viewDidLoad];
    self.view.backgroundColor = [UIColor lightGrayColor];

    TouchFeedbackScene *scene = [TouchFeedbackScene new];
    scene.useRandomColors = YES;
    scene.continuous = YES;
    [skview presentScene:scene];
    //    [SpriteVisualizer installToParent:self spriteKitView:skview visible:YES];
}

- (void) loadView
{
    self.view = [SKView new];
    skview = (SKView *) self.view;
}