Do you have an IG CFD account to trade shares or a IG share...

Do you have an IG CFD account to trade shares or a IG share trading account?
What's the minimum investment per order?
Do you know whether it's possible to sell down to 1 share?

If as suggested on the link that you receive an email asking whether you want to participate in a SPP that seems to be a great way of setting up a SPP Harvester.
Do 3 trades initially in the first quarter to get the fees down to $5 per trade then setup as many or as few as you want going forward.
Could just expand it by 25 or a month once you setup the 300.

I'd be a lot more confident dealing with IG than Superhero, I've always found their customer service to be great.