I hate to throw stones, but one of the objectives is to deposit a weld with equal legs.
Next, the final polish needs to be done with finer grit. I use a granite surface plate with 1200 grit for the final polish. It is a pain in the ass, but the surfaces have to be perfectly flat when the sample is ready for the etch. Start with something like a 400 grit, progress to 600, then 800 and 1000 grit. Each polishing operation should be oriented 90 degrees to the previous operation. Like I said, the final operation should be with the 1200 grit. Cut away the excess material (butting and nonbutting) before starting the preparation will make the job easier. That way you are only polishing the cross section of the weld and a little base metal.
If you look at the third photo, there appears to be incomplete fusion in the root extending up on both the butting member and the nonbutting members.
A better polish and close scrutiny will most likely show a similar problem with the other samples.
It is interesting to note the void in the root. It shouldn't be there.
Best regards - Al