Tigerle, sounds like you are being really sensible as you evaluate your options. Really good to hear the gifted program supports study skills and writing. Very important to school success for anyone and often overlooked in gifted kids with the assumption that everything is easy for them or they will just intrincally know how.
Mon is right, you need to check in with DS about his needs and feelings. We found with DD that had to be done in a very non threatening, casual way. Even when it was low key the concept of choice could be overwhelming for her (I don't know about anyone else but with DD and my gifted cousin, giving them choices was akin to administering a paralytic at times, even choices about dinner or what to watch on TV).
When we thought about DD moving into full time academically gifted class for fifth grade, she was 8 turning 9 at the start of that class, she was terrified more than reluctant. Admittedly she was in a very bad emotional place because of the inappropriate fourth grade placement. We had to have a well planned exit strategy, the old school would take her back, and be very positive ourselves that the plan would work. It absolutely did but DD couldn't see past the fear of change. After one day she was happy in her new class and was able to voice how unhappy she had been at the old school. She wouldn't say that before because she she didn't want to leave the devil she knew.
If your DS is reluctant to consider different options explore them gently over time. Try and tease out what might excite or scare him. But just be aware that fear can be a difficult thing to see beyond for anyone, let alone our intense little people. They may look to you to take on the decision and be the confident one for them. I find that a hard balance at times. I certainly don't want to push DD but I don't want her missing out because her fear is bigger than her ability to see.