Hope I didn't make things more confusing. Sorry.
VMD and cc are just a means to the end if you are using dippers or the Lee disk measure. I do use the disk measure so I am used to thinking about cc+vmds. (The perfect Powder Measure does not use the disks.) All you really care about is the weight of the charge. In general it dosen't really matter how much space the charge takes up as long as it fits in the case. With HP38 and .45 APC you will not have any issues.
I don't know if you have to drive someplace to shoot or can walk out your back door and shoot. If it takes some time to get to where you have to shoot I would load some a 5gr, some about 5.2 and some about 5.4.
(these don't need to be exact on the steps 5.3, 5.5 would work as well) (The Lee perfect powder measure would make this easy to do)
Here is a thread about different ways to mark them.
http://www.thehighroad.org/showthread.php?t=774423
I like to take different color sharpies (permanent markers of some flavor) and color the bottom of the case when I am working on a developing a load. I then make a note as to whats what.
For example green =5, blue = 5.2, black = 5.4 That way if they some how get mixed up you can tell which is which. Shoot the 5s first, then work your way up. Bet you will like the lower end of the scale, they will shoot softer than factory ammo, but you may want "full power loads" so those are going to be at the higher end of the charge range.
As always, Walkalong has given some great advice.
I'm guessing you will be really happy with your HP38 reloads.
Note: MEHavey was showing data for 200s and you have 185s. You will be safe using data for a heavier bullet with a lighter bullet but not the other way around. Remember Heavier bullet = LESS powder.
Also remember never start at the MAX charge. Some companies, Alliant for example, only show the MAX charge on their web site. Nothing wrong with this you just reduce the max by 10% to start.
Be safe, enjoy and please let us know how it goes.