You should probably call your guide and ask what he recommends for his area!
But I have ran bear baits for more years than I can count. My experience has shown me that most of the bear in my area hit the baits at almost dark. There are exceptions but most are dusk. Add the deep woods and it makes things hard to see. I have had to remove the sight hoods off rifles to try to see the front sight. The red dot scopes work well at baits as do illum scopes and regular good quality scopes (read light gathering qualities).
A fellow that shot a good bear off of one of my baits with a scoped rifle last year said "I couldn't see the cross hairs on the bear so I just centered the whole scope picture on the bear and pulled the trigger. He vowed he would never use a black recticle again for bear hunting and said that one of his lighted recticles would have been a perfect choice. I do not know about that because I have used scopes with black recticles that really brought in a lot of light.
Now all that said I personally use a iron sighted pistol most of the time, once in awhile I will use a Iron sighted rifle. I find tracking them with iron sights is easier than a scoped rifle. If your like most hunters using a guide, you are pressed for time. A four or five day hunt, maybe a little more. You will want every advantage you can have and spend every minute you legally can on the bait. The red dot's or scopes will assit you in that. But for me who is not in a hurry to fill my tag and have many baits I can hunt. I opt for iron sights.
Distances: In the past I put bow stands at 15-20 yds. My gun stands run 25-50 yds from the bait. Depending on wind movements in the area. If a fellow with a pistol was going to be hunting one of my stands, I would most likey put him on a bow stand, unless I knew him and how he shot with a pistol. Also I put my stands at least 20 feet high for scent purposes. I used to think higher was better, but a fellow I know uses ground blinds and his hunters seem to have as good of luck as anyone. So I am tending to re-think that one a little.
I am no expert and I bet there are a few on here that have as much and probably more experience than I. But I have baited many many years and taken my share of black bear. The area/bears/baits you are hunting may or may not be the same as my area. I know that I have lived in other states and baited bears and that the bears behaved a little bit different than they do here in Maine.
The best advise I can give is: If I were you and booking a bear hunt, I would talk to the expert in that area (my guide). There ain't a guide around that wouldn't be thrilled that you took the time to ask questions before you showed up.