Honestly I'm not sure. IF it were cartridge, I'd go with a bigger filter. The size of the pump has more room to wiggle, lots of people get by with a 3/4 pump on the same size pool that other people use 1.5 hp pump.
But I believe with filters, the larger the better, at least that's the case with cartridge filters....it's important to pair the pump size to be adequate with the filter size, not sure what that recommendation is.
But 60 sqft for a DE filter seems small to me, but I'm not real knowledgeable about DE filters. It might be fine.
You know who could help you better, "WASTE" or Ted is his name. He knows all about pool equipment and such and he'd give you good advice I bet. If he doesn't come along shortly, send him a PM.