I don't have much advice, but I do have some articles to recommend. I've got a collection I've been building to share with the school.

Inside Out: Understanding the Social and Emotional Needs of Gifted Children (Linda Silverman, 2005)
http://www.pegy.org.uk/Inside-Out%20PEGY%20pdf.pdf

The Educational Experience for Students with Gifts and Talents (Jolly and Hughes, 2015)
...if you can't find it, PM me

Hoagie's has some articles explaining IQ scores and levels of giftedness.

Understanding, Diagnosing, and Coping with Slow Processing Speed (Butnik, 2013)
http://www.2enewsletter.com/article_2013_05_slow_processing.html

If you google for "gifted and slow processing speed" a bunch of things will pop up.