I have already set a 4" deep bed of recylcled concrete as a base, leaving myself 3 1/2" to the top of the sidewalk.
Next, I will order the sand for under the pavers. The pavers themselves are 2 3/8" thick.

My plan was to use 1 1/2" of sand, allowing for 3/8" of compaction...But I just spoke to a different guy at the stone place, and of course he told me something different!

My question is this...If I use concrete sand under the pavers, how much will the sand settle when compacted?
It is not too late for me to make adjustments, but it will soon be!
Thanks.

What did the guy at the stone place say?

The second guy said that 1 1/2 inches will compact at least 3/4 inch.

Usually a little bit off wouldn't matter, but since I'm lining up to the sidewalk I don't want a tripping hazard.

I've already really compacted the base, using a vibratory plate compactor, and everything I've read says to use this again after the patio is laid. This is when I expect the sand to compact.