stick with the 12V head. Just do a p-pump conversion later. The 12v injectors are better suited for the p-pump.
Although, I've never heard of a VE pump 24v. Could be something to try and a little cheaper as long as the
VP44 lines will work with the VE pump. Never know, it may run alot better than a
VP44 24v. The pistons are different between the 12 and 24v though. Would probably be just as easy to put your VE pump and timing case on the 24v motor and drop it in.