About the slow Scrivener startup times, it depends a lot on your initial layout upon opening Scrivener. Some users tend to load the complete Draft folder in Scrivenings mode. If you close and reopen your project, this results into loading ALL Draft files all at once upon startup. This is a very heavy operation. The power of Scrivener is that you can work in chunks. Switch to any other view Mode (Corkboard, Outliner) or simply select a sub-folder, and Scrivener will load much faster for you. Loading and always working with your Draft folder in Scrivenings mode is an overkill, which still works, but will cost you few seconds of extra loading time.
Very Big embedded images (sometimes I have seen embedded images being ~10 Mb and more) are also another main reason for slow loading times. Imagine having multiple very big images in the same document and this document needs to be loaded upon startup. This is definitely asking for slow startup times.
Check your project for some of these common reasons for a startup delay and you might get your project loading much faster.