Provided your written investment strategy says so, the SMSF is able to invest in warrants and juniors.
In regards to running a SMSF as a business, I would think it again goes back to your written investment strategy of whether you can invest in juniors. Plus, I have not heard of any limitations on how often you can trade.
I can recommend a book called Self Managed Superannuation Funds by Max Newnham. I picked up my copy at Dymocks and it is available online.
As the saying goes Do Your Own Research and I am not qualified to give financial advice.
