If you lose to the boss you are allowed to use the dyom menu to skip to the fight.

It's your choise but here is how:
1- load the mission in DYOM.

2- Tools>teleport to objective>press N until you reach objective 16(It is a CJ with pickups nearby)>press left shift to tele

3- Objectives>Select objective

4- open menu>tools>start from selected

and to install the sounds you need to paste the SD folder into: Documents>GTA San Andreas User Files
If you did it right you should hear a sound at the start of the mission.