Using Refractory Mortar to skin Vermicrete dome

[Gulf]

Here is a link to an answer to a similar question a few weeks ago. I did not want to say it but I totally agree with the advice that was given.

[Gulf]

I'm afraid that Toomulla is right. Also, the needles may work in a full thick cast dome. But, I would be afraid of them in a parge coat. If the parge with needles fails, they could end up in your food .

EDIT: Just wondering if this oven is another victim of the infamous medicine ball vermiculite/perlite video?

[Toomulla]

I would expect any skin coat applied to the inside of the dome to fail

[desmodici]

I know this is not ideal and may be a silly question, but I'm looking to see if its possible to use Refractory Mortar (purchased from Forno Bravo) to apply a skin to the inside of a vermicrete dome that I just completed.
The only Refractory Cement I can find local is Rutlan, which seems to have mixed reviews when applied with a trowel (seems to need a form). I have a lot of Mortar so wanted to check and see if that would work in place of cement for a skin.

If not, Alternatively, can the mortar mix be modified to make it more suitable to use as a skin? (I also have SS Needles if that helps)