I typically let mine warm up for 24 hours. The temp will get up to 99.5 in an hour, but it usually takes longer for the humidity to stabelize. I always put the turner in and plug it in, as the motor on the turner will generate a little heat which will effect your overall bator temp.
It has been holding steady at 100-100.2 since last night, so I went ahead and put my eggs in. I'm not too worried about humidity at this point, it's been 40%+ in my 1583 for weeks with no water in it.
It is still holding right around 100*. I think the highest it got was 100.6, so that's not bad. I'll leave it alone for now, my other bator will have plenty of room in a week, so I can move these eggs then if I decide to adjust it. Thanks guys.