I don’t know exactly what you mean by wintersowing. There seem to be different methods that all get pushed under one umbrella term. I haven’t done wintersowing with peppers, but I have done direct sowings in the spring to mimic volunteering. I don’t even have the change to wintersow. Your climate they might even overwinter although I don’t see the advantage of that compared to direct sowing in the spring. They will anyway only sprout once the temperatures are high enough long enough. In some climates volunteers or those sown too early might come up too early and risk being wiped out by late frosts. I don’t know if your climate is that varied. They would need quite warm weather for quite long for the soil to warm up enough fot them to emerge. Maybe not a problem for you. Might be a good time to direct sow there if you want to try that. Just have to consider that those sown get equal exposure to sun in order to have equal selection pressure. I have found double row in east-west bed to be the best. Otherwise single row in the more sunny side. Other factor to consider is that it’s better to oversow a lot. There will be variance from genetics and luck and so the more you sow the less it’s affected by luck. This means that you need to cull quite a lot and quite often. You can look at my trials from last few years for some inspiration.