However I just looked at post below and am now thinking it might be worth my while to do some solo raids on my own with a lucky egg and stardust star? Or have I got that wrong and the higher rewards are only for Moltres raids (which I obviously can't do on my own).
tumpymummy From 10am to 1pm all gyms will only have Moltres, and a recommended 5+ players are needed.
At the moment, during this stardust event, all raids regardless of level are a guaranteed 3,000 stardust, so that may be worth a star piece if you’re doing a lot of small raids in an hour (as star pieces have been extended from 30 to 60 minutes for the event) and/or a lot of continuous hatching and catching during that time.
If you’re not doing a 5 star (legendary) raid, it is not worth putting a lucky egg on, as the XP rewards are too low (3,000/3,500/4,000 for level 1/2/3 raids respectively). For legendary raid you can earn 20,000 XP on a lucky egg.
The higher level raid you do, the more (and better) rewards you will receive, and more XP as well (usually same with stardust, the higher the raid the more you get, but with this event all raids are guaranteed 3,000).