After much practice, my sage advice:

Start with FBM, dial voluptuous down to between -4 and -6.  This affects the full body, but results in much more realism.  This is critical - starting any other way will yield unrealistic results.  If you don't like the overall shape, change glutes, thighs, arms, whatever - separately.

Now adjust breasts, dial 'size' and 'large' down until you like the overall size.

Fix the distortions (they will be there) as best you can with other adjustments - among the helpful are diameter, cleavage, straight out, perk and ariole out.  Natural can also be helpful - use it in the negative direction to fix the bottom shape.

This is the only way I have found to achieve small realism.

Lotus 123 ~ S-Render ~ OS/2 WARP ~ IBM 8088 / 4.77 Mhz ~ Hercules Ultima graphics, Hitachi 10 MB HDD, 64K RAM, 12 in diagonal CRT Monitor (16 colors / 60 Hz refresh rate), 240 Watt PS, Dual 1.44 MB Floppies, 2 button mouse input device.  Beige horizontal case.  I don't display my unit.