I’m a big fan of the Z-Trim wing but surface buoyancy does seem to be an issue for a lot of people, at the start of the dive this is less of an issue – It’s more at the end of the dive people get worried. If surface buoyancy is an issue at the end of a dive it can normally be solved by letting the tanks hang – i.e. removing the bungee attachment.
This is best done while still underwater, I normally remove the long hose, coil it and clip it to a small bungee around the tank neck before surfacing, it’s also easy to remove the necklace from the primary (left) tank and untie the bungee attachment while still 1-2m underwater, hold the tank in place until your at the surface, inflate then pop the LPI connection and let the tank hang – this keeps both tanks in the water and therefore neutral or positively buoyant so all the BC lift is used for you, not holding tanks above the waterline.
If this still isn’t enough you can always use a DSMB on the dive and use it for additional support at the surface, or even add a small MSR style bladder under the Z-Trim. The Z-plus or Alpha/Delta would be better for the surface but my is that it doesn’t work as well for trim, especially when lightly loaded with air as it moves around a lot. The razor BAT wing has the same issue, especially as there are no baffles in the wing itself.
I don’t have any experience with the XDeep Stealth BC but it looks nice. My first reaction was that it was just another variation on the MSR hydration pack like the Bat wing, but on closer inspection it looks very promising. It could be the best option out there right now as the workmanship looks top quality but it’s hard to say without trying one out – looks like it could be my next purchase!
Given your current equipment I’d suggest using the tank hang or additional buoyancy device as a first instance, obviously the surface is important but at the same time you don’t want to give yourself more problems to solve one problem.
Karl