When offering preferred stock to investors as a self-funded searcher, which of the following is the most common?

1) Defer preferred stock interest payments and investment payback until sale of company
2) Pay back as cash becomes available
3) Pay just the interest as cash becomes available and defer paying back the investment portion until the company is sold

Also, in any of these cases, if the interest and investment are paid back, does the stock usually convert to common at that time? Are future dividends then split according to common equity %?

Looking for some examples of this or for lawyers who have created term sheets for self-funded search investors. Thank you.