Yes, you want plants that exhibit a totally red stem on the waterleafs, the main stem coloration is varible now to an extent. Look for compltely red stems on the waterleafs, Look for really dark green coloration on the fan leaves, much darker of a green than the rest, much like well fertilized Bubba and Master get also. It also has a mutation that pops up, usually found on the bottom leaves of the plant, this is when the 3 middle "fingers" are slim and overlap each other, almost looking like an f-18 looking at it from the top view. It doesnt happen on every leaf, maybe once or tops maybe 4 or 5 times.
I have noticed over time now, that the all totally purple stemmed plants are beautiful. They have gorgeous coloring to them and grow much more sativa like with colas more like long spears. The fleshy all green stem tend to be more of the indica type, but dont let that confuse you. When I say indica, im only reffering to the way it bushes out, they still get just as tall as the sativa type flowers and structure. Then there is the stems that have purple striping. Id say the purple striping phenos more often show UD traits as far as being identical, but I have found plants on the sativa side that are soo dam frosty, its unbelieveable. Then there are the monster yielders that dont have quite the same amount of resin, but that dont mean they are slouche4s. On the contrary, they still have more resin than most shit out today. My suggestion is to just clone all your females, do your run, cure your herb, smoke them all over a months period and see which jar goes empty first second and last etc. Then keep that plant...