I think that tank isn't big enough anyway Billaney.
The problem is surface area for Oxygenation.
As I'm sure you know they build bubble nests under items at the surface ( the lid of a small poly box works a treat as the edges hold the bubbles).
The eggs like corys need good oxygenation too.
When taking into the account adult hoplo's are meaty fallows, the eggs need good aeration and something like 1/3 to 1/2 of the surface area will be covered for the purpose of holding the bubble nest it would leave inadequate open surface area.
They may well spawn in that size tank but it would be likely most if not all the eggs would die.
The fry are gross feeders and pollution can be a problem too once the fry reach 1.5 - 2cm.
A tank 75 - 90cm long is recommend because - the above reasons.
Good luck finding a male, they are really interesting to breed.