Most folks will probably answer that a bouyant ascent shouldn't weigh heavily in your decision making process. Your dives should be planned in such a way that you never run out of gas and short of being attacked by sharks allows a slow controlled ascent.
With regard to how to split your weight there are a few things I would consider:
1. How much weight is required by you, your exposure protection and your rig to achieve neutral bouyancy at or near the surface? This will accomodate comfortable doffing/donning of your bc both on the surface and while submerged. And should be all the weight you require for your dive.
2. Ditchable vs. non ditchable. For average recreational dives(not drysuit, cold water), all this weight should easily fit within the ditchable category, regardless of whether it's on a belt or in integrated pockets. Although, after considering the above, you might want it on your belt. The only reason I might want to move some of this weight to a non ditchable position is to aid in trim.
3. Non ditchable weight. If you're using a stainless backplate or steel tanks or other non ditchable weight, you will be negative by that amount if you were to loose bouyancy while at depth. Hence the reason why people who are utilizing largely non ditchable weight also tend to ensure that they have redundant bouyancy in the form of a dry suit, 2 bc bladders or an appropriately large smb or lift bag.
Does this make sense and help answer your question?
