Neck reining you can get away with using many types of bits. Tom thumbs are my absolute least favorite bit because the communication isn't clear.
That one you've got isn't bad, I kinda like it actually. The only thing I'd consider instead of a curb strap I'd use a slober bar. A slober bar holds the two shanks together so that when you neck rein it turns the bit more correctly in their mouth - I can go into details if your interested. But I love the short shanks and high purchase, that's barely a step up from a snaffle if you don't use a curb strap - it's a more clear communication without being overly strong when compared to a snaffle. :)
I'd use a slober bar instead of a curb strap honestly (not that they're mutually exclusive you could use both, but I don't see a need).