Sometimes the scion can take a bit to get jump started. I wouldn't worry too much about it unless the scion starts shriveling. From what I can tell, 2 of those grafts look very promising and the others are a wait and see.

With that said, day 35
1 August 2018

37 days old
3 August 2018

40 days old today
6 August 2018

Here's the same graft that I posted a few days ago... Not sure how long its been since it sprouted from seed but I'll keep track of it since it was grafted..

Believe is either a reynolds X sso02 or Icaros...

That one is looking nice and pink purple so I know your pushing her effectively.

I'll raise your graft with a sideways grafted seedling.

Here it is today:

Looking good Spractral. You can see this one is really starting to take off.

Thanks man.. Now if these seedlings keep popping and stay healthy and get grafted. That'll be awesome.. and if this one takes..

Please tell me you wrapped this one with parafilm after this picture. A variegated crested pachanoi areole deserves nothing but the best.

Yup it was wrapped... had a look today though and some of top of the parfilm has dissolved and with it the top part of the scion has moved itself away from the graft... so it may end up being partially grafted or have to be redone...

Here's its cousin today :

Your grafts are really looking good. Looks like the armpits/areoles need to be scratched a bit on a few of those grafts to keep the scion growing fast though.

Let me share day 48 with you first and then a nice hybrid as well. The picture on the hybrid is not the best, but I'll get some more photos as the days progress.

Hot baby in the sun busting through the parafilm

L. jourdaniana

More grafts of some hybrids I've got going. Notice the purple and red color. I prefer to see more red at this stage, but purple is alright as well. It ensues I get nice round squat seedlings and nice fat scion growth as well when grafted. No etiolation here if I am watching my p's and q's.

Inyan, will u keep that lil jourdaniana in full sun also??

I try to keep most of my jourdaniana in the brightest spot in the yard. If you will note, the brightest red ones above are in fact jourdaniana. I love my hybrids. What can I say?

Wakinyan, I often read that red color is bad for small seedlings and they should be placed under reduced light to avoid such coloration, as it is recognized as something wrong. I see you don't bother and have them under full sun. Let me ask few questions :

1. I understand you found it beneficial, so it has to have some pros. Does it have any cons?
2. is it just for some kind of cactus or for all? I am particularly asking about Trichocereus
3. is it in fact good for every graft to be under full sun from the start or is it just a part of your selection strategy to find the strongest specimen?
4. when you use peres as a rootstock, do you grow it under full sun as well before you graft onto it?

First, while I do grow many seedlings in full sun to get them to that nice red color or purple if a little less sun. I don’t worry if I forget and leave some seedlings in the shade and they get a bit etoliated. But, here it is in a nutshell. You see many people growing etiolated seedlings whether they be Trichocereus or Lophophora that appear very pale green and long. My preference, is for nice thick fat seedlings whether they are Trichocereus, Lophophora, or any other cacti. I want them to have some girth.

1st pro…. Red or purple seedlings if grown in full sun from the start will rapidly turn their adult color within 1 month of being grafted if they are actively growing whether that is a Trichocereus, Lophophora, etc.

2nd pro…. Your seedings will not be etoliated.

1st Con… if your grafting without parafilm… many will move those grafts to the shade and put them in humid environment. Note, that is only a con if your not using parafilm to graft.
As regards your second question, I can’t speak for every cacti as I haven’t grown each and every cacti. I can say that you will have fine results with Trichocereus seedlings or Lophophora this way.

3rd question. If your not grafting with parafilm you are likely going to want to move to the shade once you have grafted. This slows down the drying out process of the tissues with grafts not protected with parafilm.
If your using parafilm, you will want to keep your grafts in full sun and water them before, during, and after grafting to ensure you get rapid growth.

4th. I grow Pereskiopsis in full sun and in the shade. The later is largely out of laziness. I sometimes till a row or two outside in full sun and plant my Pereskiopsis like one might plant rows of tomato plants in full sun to get a few going for propagation. I may graft to some of those or I may not. Left unattended some of my Pereskiopsis plants have a tendency to grow like brambles while others will reach heights of 5-6 feet without branching.

With that said... one of these hybrids is not like the others. That one shall be grafted. Notice how these seedlings are not bright red... they have been neglected and allowed to grow only a few hours in direct sunlight each day.

Thanks for your reponses, Wakinyan. So I will move my peres under full sun, as it is already being rooted. The season is going to finish by a month here so it can absorb the last sun and then it will go under fluorescent lights in my new grow box, which is just under construction.
I believe by this time it will be ready for grafting, so I can finally start with it too

Aliens eating my cacti... noticed this while doing my first soak for my seedlings. Note, these seedlings are a little etiolated... not at all how I like them.