S. the 30 minutes/1/2-inch heat diffusion rate is a general approximation, but it's not a linear rate which is why SV cooks have more time challenges with large cuts of meat as you plan to do in the future.
A bone-in roast done by a conventional cooking technique, which is usually by convection, - heated air, could be preferred as the bones act as a rack allowing air to circulate around the roast. Bones also retain heat providing carry-over heat to finish cooking which doesn't happen with SV. You likely know heated water has approximately 10X the thermal efficiency of air which is why the SV technique differs so much from conventional cooking.
Community members find Baldwin very informative.
His cooking time guide for tender meat is the following table:
As M-Hand suggests you might consider brining your next pork roast before cooking. It helps maintain moisture content. I think of it as an essential for pork chops, but i also cook at a lower temperature.
It's not been my experience that dry rubs release a significant amount of water content from the meat. Heat does that. Salt ions do too. However the moisture released by salt is reabsorbed by meat at room temperature in about 45 minutes.
For your SV cooks, only salt penetrates meat for flavour enhancement. The dry rub doesn't stay dry when vacuum packaged and becomes diluted. Apply it if you want to, but it's will have greater effect when applied before searing allowing the aromatic elements to be more noticeable. Alternatively, diluting your dry rub and injecting it into the meat will flavour the meat as it cooks.
A trick i use when serving pink-adverse guests is to blot their meat portion with a wad of paper towel. It absorbs the pink meat juices so the meat's appearance approaches that of well done, but isn't.