I agree with Gary where 260 should be attainable but 300 might be a stretch. It’s good to set goals but goals need to be attainable. Then you set your next goal.
At 45, shit your still young… go for it. Make sure you stretch before you do it. As for the Orange Whip, we have them at our indoor teaching place. They are for tempo , not building speed. You’ll never find anyone using it for speed. It’s not designed for that.
Also when using my Superspeed clubs I make sure I take a bigger backswing and swing hard. If you end up doing the speed training let me know, there were a few pitfalls I came across in my training at first that I can help you avoid.