Salsa is recorded in several different " styles-- notably, Romantica ( sometimes called Monga ) Dura and Descarga .Add to this Cuban " Son " and all the variations by different countries ( Cuba-- Panama-- Venezuela- Colombia-- PR and NYC etc. )
As you can begin to see- the music is very very complex.
Fast ( descarga ) is not wrong-- but IS wrong for a beginner-- on the other hand-- the very slow tempos are more difficult to interpret .-- mid range is what i teach to my beginners, and the variety is endless.
Romantica, by the way, does NOT mean slow, its the type of Singer associated with the style .
Most Son is a very good pace for beginners and the music is the original form ( Son Clave )-- if your DJ knows anything about music he will have some . If not-- I can reccomend several .
I should add-- that Cuban Son is a style that defines a break on "2" rhythm to the trained ear -- but 1 will work .