I am a very hands on hatcher. But I have staggered hatches so there is just enough time to clean the "hatcher" between. I try to mentally note when certain eggs pip/monitor progress and I use a plastic egg tray for hatching. Humidity that high(above 75...some ppl even say 70) for extended periods has been known to "drown" chicks in the egg and that many would make a mess quick, might not have as much poo but they still have some from the absorbed yolk.I do usually remove chicks when oldest are 2-3 days as long as they look dry I feel they are fine to move. I haven't worried much about external pips, if humidity is low after I've had it open I just add a bit of water to bring it back up to about 65. I'll be honest I've missed a couple eggs(in the far back that are difficult for me to get to because of shelving my 3 incubators sit on) and had them hatch no problem in 25% humidity. Not suggesting that, just saying I personally have seen too high humidity do more damage than too low humidity. One of my incubators was designed for reptiles and has a foam liner in bottom but too many air holes so until I taped them I was having trouble keeping humidity in there was always 20-35% and had a few hatch in there without trouble. I've also handled moved externally pipped eggs that I noticed were a day or two early(in my first few test runs with incubators) and still had them hatch. So use your best judgement from what you have read and are comfortable with. Either way there will be losses even if everything is done perfectly!
Kiawaki, Do keep in mind chicks will produce a certain amount of heat so that many chicks and poo from absorbed yolk is what spiked the temps and humidity. And that is not good for the chicks. So I hope by now you have them happily settled into their new brooder.
Heat mats are really a great option in this weather and at a week old I've been turning mine off for the hottest part of the day(when its 90 here) even on week old chicks. The mats I find are best purchased at tractor supply at the end of fall they'll go on clearance for about half off but otherwise they are only around $30 I believe. And compared to the cost/risks of heat light it is a really good option. Just remember chicks kept outside will need protection from drafts as well. And 4 weeks is a good approximate age for this time of year, it will be a little colder than ideal but they will huddle and create some of their own warmth. I've even stuck a few larger 3 week old chicks outside with some 4-5 week olds and they've done well. Honestly only chicks I've lost outside were a couple bantams with some silkie hens and it was probably the hen as it was her first hatch and I don't think she was quite as attentive as she should have been.
Best of luck both of you!