Here is the skinny how i do it..... Strip the whole head down( unbolt everything) till you have the chassis. Wipe it down with laquer thinner or better yet a urethane reducer(body shops use this) what this does is cleans the tolex then it gets soft and the pores open up. Go to autozone, paint store whatever and pick up a few cans of VINYL Spray. As soon as your done wiping the tolex spray it, nice light coat first then the next also alternate the spray pattern up down/ then side to side this gets all the pores.
This is the same method used in a body shop to do interior body panels, plastic parts vinyl parts, once it dries it looks awesome and no it doesnt chip or peel or whatever you may think this is special paint for this, ive done cabinets and heads, everyone thinks I re tolexed them.... you can do a head for about 20 bucks..CJ