Reddit reviews An English Dictionary of Basic Japanese Signs

I teach ASL in Tokyo and can get by in JSL. There is only one JSL-English dictionary, published by the Japanese Federation of the Deaf. You can read info about it here but I don't recommend ordering it through them - they seem to charge a lot for shipping! Amazon JP used to have it, but I don't see it there now. Amazon US has it listed but it's way too expensive through them. I could try to get and send you a copy if you want - it would fit in a large padded envelope.

You mentioned being on the West Coast. If you're anywhere near the Bay Area, Ohlone College in Fremont has a partnership with the Nippon Foundation - there are usually half a dozen deaf Japanese students there at any given time.

The Japanese Federation for the Deaf did make an English dictionary of JSL, but it's quite expensive unfortunately as it's out of print:

https://www.amazon.com/English-Dictionary-Basic-Japanese-Signs/dp/4915675408

It's not quite as useful as a dictionary, but NHK does sign language news that comes with very clear subtitles (with furigana on all of the words too) - might be a good resource.

http://www.nhk.or.jp/shuwa/

Edit: looks like there's an app that teaches some basic phrases in English too. Found it via this Tofugu article, which also lists some good youtube resources: https://www.tofugu.com/japan/japanese-sign-language/ (sorry if you've read it already!) Since the grammar of JSL and spoken Japanese are quite different, the signs would probably be most helpful for nouns and simple verbs and adjectives, but I think this is a great way to enhance your Japanese learning and I hope you are able to continue with it! I'm sure JSL speakers (signers?) would enjoy teaching and working with you too if you have a chance to come to Japan someday.