I am not familiar with the HiBlow pumps enough to have seen their Pond Size recommendations. Besides that, I don't see how they can even start to recommend a pond size without considering the quality of the diffuser. It's not the amount of air the pump puts out, but how it is diffused. Smaller bubbles means more water movement.
Here is the pump curve for the HP-60 and 80...
These curves are very similar. The 80 has just a bit more oomph, which you probably don't need. Both pumps are rated at 2.13psi. This is where they run the best and will last the longest, but you will be running at more like 3 to 4 psi. Not too big of a deal really (yellowish dotted line).
The pump will see about a 1/2 psi per foot of water depth that the diffuser is placed in. If you put the diffuser/s in 5 foot of water...that will add 2.5 psi of back pressure on the pump...a diffuser (or two) will add about another 1/2 to 1 psi as will some plumbing and hose (additional 1/2 to 1psi). This puts your system at 3.5psi if designed well (the right size line, no plumbing restrictions, and the lines don't get too long).
Look at the chart and find the 3.5 psi mark at the bottom. Draw a line straight up until you hit the green line (60 herts pump electric line for the USA), now draw a straight line to the right and you just under 2 CFM for the 60 and very close to 2 CFM for the 80.
Vertex rates their diffusers at 1 CFM, Matala rates theirs at 1.5 or 2 (I can't remember). I am sure that they can handle more, but it might shorten the life and/or reduce the lift. So, this HP-80 would like to run 2 Vertex 9" diffusers or slightly over-drive 1 Matala with the above example . Either way, it will be plenty of water movement for your pond. You might want to run them with a timer for only a few hours a day, or not....depending.
If nothing else, the above mumbo-jumbo gives you an idea of how to size a system.