In my opinion, don’t drill too many holes because a hole is a point of stress concentration, from my experience drilling holes for weight loss is a lot of work for a very small gain.
I 100% agree, especially in the two ribs that hold the mounting tube and are therefore very high stress points. Take weight of the tips, for instance, by all means. There is at least as much meat to take off there and they are not points of high stress. It will also have the effect of reducing the interia when rolling which can't be a bad thing.
-David C