BJAnalyst said
“ Also if you use Katarina Walker's Hi Low it is unbalanced with a pivot at a true count of four (since the 10's are removed) similar to the KO in blackjack being unbalanced with a pivot of a true count of 4 so my Table of Critical Running Counts (TCRC) for KO can be used for Spanish 21 HL also.

So my only comments on Spanish 21 are

1. Stay away from H17 games. Play only S17 games.

2. Read Katarina's Spanish 21 book and use Katarina's HL for Spanish 21.

3. Use six and eight deck TCRC (Table of Critical Running Counts) for KO for Spanish 21 HL.”

Freightman suggests that
Rather than investing tons of time on a game you don’t know and will seldom play, use hi lo, starting with -24 On the 6 deck game. Break even is about -3 as I recall, and your max bet is out at about true 0. If you get positive counts, blast away.

Whereas blackjack has a rule of thumb Of .5 increase in edge per true count, you can hike that to .7 at Spanish. I haven’t played in years and I’ve forgotten a lot. Again, if you’re going to play this game - it’s fun but it’s dangerous - it has high variance - strategy is entirely different than BJ - you’ll get hammered if you use BJ strategy for Spanish.

One last point. If you go to Pennsylvania, play their great BJ games you know, rather than the great Spanish game you don’t.