Mark great questions and as for XXXXXX I would have to measure him to see what class he would fit in. I am going to give you the height requirements to properly fit a bully into the appropriate class. The most difficult class to understand is the extreme but since you have Tombstone he is a great example of and extreme bully.
pocket female: 16" and under no exceptions, any fraction over 16" and she becomes a standard class bully.
pocket male: 17" and under no exceptions, any fraction over 17"and he becomes a standard class bully.
Standard female: 16" to 19" is a standard size bully
Standard male: 17" to 20 is a standard size bully.
Extra Large female: 19" + any fraction over 19" and she becomes a XL class bully.
Extra Large Male: 20" + any fraction over 20" and he becomes a XL class bully.
Extreme female: 16" to 20" with extreme bone and width is considered extreme not short or faulted this is where people get confused, this is harder to understand with out and example.
Extreme male: 17" to 19 with extreme bone and width is considered extreme not short or faulted, this is where people get confused , this is harder to understand but Tombstone is a good example. Tombstone or wider is a good example of extreme.
Hope this helps Mark.
here are a few videos of Porky moving but he is very young in these videos and is much bullier now.