Mark,
Other than with GM Ted Buot and Maybe GM Remy Presas, I have not trained with anyone of the Balintawak lineage. The Grouped version would have been more of the Villasin lineage. (GM) Toboada, from my undestanding trained with Pilo Vilez (GM), and (GM) Joe Villasin, and even with GM Anciong Bacon. As GM Remy Presas was of the (GM) Mongcal and (GM) Maranga. This would have been more of the modifed version, to use Rocky's terms

. So, I do not think the Tapi-Tapi per se was Balntawak. In the Balintawak as taught by (GM) Ted Buot, there is no grabbing or let me say very little grabbing, and only for certain techniques for disarms, etc.
Some people have made the comment that GM Remy Presas created Modern Arnis to counter Balintawak. As I was not told this, by GM Remy Presas, I do not know this to be true. I do think both are good arts and can be used effectively.
So, to say the Tapi-Tapi is like Balintawak is to say it is like Seguidas the Fundamentals or the Abecedario out of order. It could also be in the Corraidas where the mixing bowl or the free sparring portion comes in. So, yes there are similarities, yet there are obvious differences from my perspective of teachers.
Clear as mudd Mark?
I have to go, I will reply back later and try to maybe clarify, after I have had more time to put my ideas into words.
:asian: