There are low cost ways to hold a diversified basket of preferred shares. The iShares' CPD - S&P/TSX Canadian Preferred Share Index Fund has 173 different holdings in various sectors. The distribution yield is 4.78%.
The current Management Expense Ratio (MER) is 0.50%, meaning that over 10% of the return is going to manage the fund. Are there any strategies that could help you get that back? You could simply go to the holdings list and start buying the same individual shares in an online discount brokerage account and have no yearly management fee.
The problem with this approach is that your trading fees will add up and you will not get the diversification of the fund. Splitting $50,000 in 20 stocks at $2500 each will have a trading cost of $200 (assume $9.95 trades at Questrade) or more - that's a cost of 0.4% of the investment. Obviously you are not much further ahead. Purchase larger amounts, with cheaper trades, say at Interactive Brokers, and this could work. But since Interactive Brokers does not have registered accounts, get ready for a lot of paperwork.
Another strategy is to buy shares on first issue and hold them at one of the big banks' brokerage arms. This avoids the up front trading fees. Because banks get a fee at the time of sale it is possible to have an account that holds these shares but has no annual fees. This is not their typical model and it may be a promotion to get you to fully invest at the brokers - typical their would be annual fees, often based on family assets being held at the broker.
PS - As noted before there may be no better strategy than holding the Malachite Aggressive Preferred Fund which boasts higher returns enhanced by trading, a better credit rating than equivalent funds and all the simplicity of an ETF.