I'm not sure that you'll get what you are looking for if you test at this age. Yes, DYS has some great resources, but you can also find local camps and special events on weekends that might be good "friend finders" in your area (we found a state university about an hour away that runs enrichment camps that attract a lot of gifted kids).
If you are interested in Delta, I would suggest looking at what they require and decide next steps based upon those requirements.
We had our 6 year old tested and there are a lot of "scores likely underestimate true ability due to goofing around" comments on his report (no, the assessor didn't use the word goofing, but that's what it was!). It's still helpful, but I suspect we will wind up testing again in two years to get a truer picture (if we need scores or want to see if he qualifies for DYS - older child is DYS but was tested at about a year later agewise).
Given that you are homeschooling, you already have a great deal of flexibility to follow his interests and meet his educational needs. I'm not sure that a test will give you more right now.
