I have two urchins - one long spine and one that looks like yours. Both are well behaved, the only thing they harm is me when I stick my hand in their spines. They don't seem to starve for the moment. On the other hand I have far more algae than Wade does. I have a 90 gal. So, I'd say, if you have algae go for it, if it's really clean, it will starve. FYI, I have softies a bit of lps and sps in my tank, the only suspected bothering is to a bubble coral - I think that my long spine stung it a few times - one head is often deflated while the others are fine, then this recovers and another goes down. They're interesting creatures. Yesterday I watched a lot my longspine munching on some Ulva.
M.