My girls are about 2 1/2 years apart. We really didn't seem to have a terrible problem with jealousy or anything. Part of that is because my oldest was always Daddy's girl, so whenever I needed to take care of the baby, she and Daddy would go to the playground of to the pool or something like that. Another thing that helped was to really make her a part of the whole thing. Sounds like you're doing a really good job of that already.
I talked to Emily, my oldest, quite a bit before the baby got here. We referred to the new addition as "her baby". "Are you going to help mommy give your new baby a bath?" "Are you going to tell your new baby stories?" Once Eden, our baby, got here, Emily was the proudest big sister, telling everyone about 'her new baby'. She really seemed to embrace the experience. She'd always been the mothering type, so it helped tremendously that she was so willing to help out.
Here's a suggestion that my husband would have baulked at if Emily had been a boy, but I'm going to suggest it anyway.

Maybe you could buy Reed a babydoll that he could 'take care of'. Show him how to put a diaper on it, how to hold it, how to feed it a bottle, how to be gentle with it, that kind of thing. That way it all won't seem so foreign to him when the baby comes. Giving him the confidence now, before the baby gets here, that he's a big boy that knows how to take care of his little sister might ease the road ahead.
Just talk to him about the way that things are going to change once the baby comes. Explain that there will be times when it will be very important to play quietly because babies need lots of rest...that the baby might get lots of presents and he might not get so many, because it's the baby's very first birthday and birthdays are very special...that Grandma might sometimes do special things for the baby, but that doesn't mean that he's any less special to her...that babies sometimes cry a lot and it's important to try and be patient and understanding when that happens...those kinds of things. It's going to be a big change, but if you prepare him for the changes, I think it might be easier for you
Also, setting aside special Reed and Mommy dates is a good idea. And never hesitate to tell him how proud you are that he's such a good big brother and how much you love him.
I was rambling but maybe there's some helpful hints in there
Love, Heather