I recently got a ASI533MC camera which is on the way. It has a rather small sensor with a 16mm diagonal. I am not able to make a build vs buy decision on a compact 6" F4 astrograph for this camera. I was wondering if I build one myself, I can use a smaller central obstruction as the scope would be dedicated for use with this camera. I am new to this, so correct me if I am wrong anywhere. Since the required fully illuminated image circle is a tiny 16mm, I hope to get away with a small secondary ~32mm instead of the tradiional 63mm which comes with off the shelf scopes to carter to larger camera sensors. The central obstruction is 20% for the 32mm compared to 42% for the 63mm. Am I overthinking this? Does the central obstruction matter much? I understand it reduces contrast and nothing else much. Does the difference in contrast worth the effort? Just for background, I am used to DIY and have descent capability there.