I've gone through a couple of different style SMB's over the last few years due to breakage, loss, gifting etc... I personally would agree with the idea to forget a weighted SMB if it is going to be shot at depth. I personally don't like the idea of disconnecting my BCD hose to push it into the nipple on the SMB at all. And honestly orally inflating at depth seems needlessly messy and complicating, not saying people don't do it, but I've never seen it done FWIW. I prefer the open bottom with baffle SMB. I can fill them with either my exhales from primary reg, or by purging my secondary reg into it. By using the exhale from my primary I have both hands free to handle the SMB and reel, or one free to purge my BCD if needed. I have seen a number of divers flail around using the LP BCD hose attachment to fill. While I am sure that with practice it gets easier, my thought is anything that minimizes the tasks I have to do is better. For me , one hand to the left side of the SMB holding it open, one hand on the right (also holding the open center of the reel between 2 fingers) large exhale and let go is both easy, safe and simple. No need for weight since you are taking up the slack on your reel as you ascend and can keep it as tight and upright as you need to by staying a bit negatively buoyant if you want.