Egyronin,
I have a few with large leaves such as yours and it seems to be a characteristic of many Arabicums or any Adeniums from seed.
The canopy from the leaves would definitely effect any seedling growing beneath them.
I would not prune leaves. Sounds like they need more space?
All look very healthy though.
Rick

I'd have to agree with Rick, no need to prune those leaves--I have a few arabicums just like this with ridiculously huge leaves, it's just the way they are. The arabicum on the left in my photo is a Black Giant seedling that has those big leaves....while the one on the right is Desert Night Fork with more normal sized leaves....both roughly 6+ months old when the photo was taken.

rcharles,jv44 thanks a lot for your answers
rick you said they look like they need more space,u mean vertically(bigger deeper pot) or horizontally (more space side wise) ?
jv44 i have another kinda look like your desert fork.all of my seeds is the arabicum from yemen.it kinda looks better when shorter and fatter.by the way have root prune these?do you notice any difference in the growth habits?
Ahmed

egyronin,
What I meant was that if you have seedlings under the canopy of large leaves that they would benefit from more direct light.
The two plants you show, I would just leave them. May find as they get bigger that you may need to give more space between the two.
They look very happy and healthy to me.
Rick

thanks again for the help.i will leave them where they at now till spring.i know i should re pot them separate. i already did that with one.prune the roots of one and the rest of them is left alone to c if there any difference in the root development.
so far i notice the caudex on the root prone one getting a lot fatter from the soil line and taper up.the non prune ones soil line caudex is like a knuckle little slimmer and then get fatter then taper thin.
growth on root prune ones slowed down considerably.they took longer than expected to go back to somewhat normal.leaves kinda smaller than the unprune ones.i hope i didn't make that long.i tend to do that.