For this sentence, should i use present indicative, present subjunctive,

preterite, or past subjunctive and explain?
1. Ayer les recomendamos que uds. _______ paciencia. (tener)      
I think it is between present subjunctive or past subjunctive but don't know which one.


Also, for these 2, should I choose present indicative or present subjunctive 
1. Aunque (haber) varias clases abiertas, necesito la clase que (empezar) a las ocho porque trabajo a las diez.
2. Cuando (escoger) un coche nuevo, debes encontrar uno que (gastar) poca gasolina.