Focus on GST or add it to my current routine?

Next week I plan to begin Fundamentals, with a long term goal of slowly working my way through all of the GST courses. So, I'm wondering if it's best to eliminate the strength training I currently do and focuson GST or should I do a combination of both?

Well, I just saw this topic here. Perhaps that's my answer?

Basically, as long as you are progressing there's no problem in doing both. If progress slows down than you can look at trade offs and prioritize.

Spoiler alert: once you get into Foundations it will shred to pieces any strength training improv.  Not to be misconstrued as "quit everything" advice. One can still do her/his favorite sport (running, climbing, etc.) if s/he has the time and energy to do so.

Sorry, but I don't think I'm following you Eva.
So once I get to Foundations, I will:

• Lose strength?
• Not have time for my regular calisthenics?
• Not need to bother with calisthenics because Foundations will surpass what I'm doing?

Darren, let me phrase it in another way: 

Although I can’t predict the future or your reaction to Foundations, I can say with certainty that strength gains will come when you stick to the program as prescribed.

If you trust and follow the program, I think it’s fair to assume that most likely you won’t need or want to be doing random “pull ups, dips and push ups” as you described in your post. First, because it could be redundant or maybe overkill (sometimes, less is more). Second, because those elements are presented in Foundations in a progressive manner forming part of an intelligent program ladder, where one step leads to the next. Third, you will probably want to dedicate more time to mobility elements that otherwise would hamper your strength gains. Therefor those will become a new priory, time and energy wise.

Don’t worry, you will not lose. On the contrary, you will gain and build true strength from the bottom up.

All those elements are presented at low levels of Foundation training, and there is a comprehensive exploration of variations and associated mobility along the way.

Keeping it simple, the approach to take is to complete your foundation work for the day, then add some additional work if you are champing at the bit.

If you are fairly strong and mobile it will not be long before you are working variants much harder than the basic version

Perfect.
Thanks.