You can load as many caches as the GPSr will handle from GSAK.
No macro needed to just load as many as you want.
I usually load between 3,000 and 4,000 caches at a time on my 710.
I will filter out caches I've found and caches I don't want to search for, like puzzles I haven't solved or 5 star terrain.
Then filter out caches not in the area I'm going to.

I keep a file of every cache in Massachusetts on GSAK, I update it every 3 weeks or so. Over 9,000 caches.
I also create GSAK files of any trip I'm going on and will load those caches to my 710.

If you want to learn some tips on GSAK and Pocket Queries go to the FILE SECTION of this forum in Tutorials for some helpful tips.
Download the tutorial and read it at your leisure. It's PDF file.
Or go here - Pocket Queries & GSAK 101 to see it and/or download it.
I didn't make this but I do know the guy that did, he gives classes on GSAK & PQs in events in New Hampshire.

That macro to do 200 you noticed was for the old explorist XL, it would load caches in files of 200 caches in each file, based on miles from home. It will load thousands of caches but in LOC file, the XL does not use GPX.

Any questions or problems just ask here on the forum.

Phil