With using a PC what do you use or recommend for a 1 step polish? I have a lot of calls and emails lately for just a quick detail, wash, clay, 1 step and wax. I have used Meg D 151 with good results topped with OOS and on a few cars M205. I am looking to see what else there is I can try? Something that works well with a PC, I have not mastered the rotary yet
menz power finish + green or white m205 with pressure on green, white, or black those have all served me pretty well in terms of cut and finish
If you are doing a one step polish followed by an LSP I would go green CCS and Power Finish. If its a true one step, I would recommend Gloss-its One Step Machine Gloss. It works very well and will give a decent amount of protection.
Don't automatically discount System X3 or Mark V Mystique (supposedly some linkage between the two), as they are very good with various pads.
If by "one step" you mean something that polishes and lays down some sort of protection in one product, I understand Meg's 151 is quite good. If you're looking to do one polishing step, and lay down LSP independently, look no further than Menzerna Power Finish. Best polish I've got on the shelf. It's capable of a surprising amount of correction, yet finishes down LSP ready if worked long enough. Power Finish and an orange LC pad (or a yellow 3M UK pad) always blows me away.
