How to deal with these Besser blocks? Paint or fill and render?

[DarylS]

Hi All, 

I'm deciding between painting these breeze blocks Colourbond Dune or if i fill them with something (maybe expanding foam?) then trimmring that level and rendering over it (Medium Texture Dune). The Breeze blocks are backed by Cementboard on the otherside, and it's heavily glued into place. 

My questions are...

1. If i was to paint them, is spraying the way to go, could i get a paint brush in there? Would that be a pain in the...
2. If i was to render it, what's the best way to fill the breeze blocks so they're level with the surface of the face bricks (My thought was expandding foam? Is there a better option, would it be possible to seal expanding foam prior to applying the render? Is that necessay as the render itself would act as a sealer?, then i can render over the top of it? 
I can't place cementboard on the front like the back as the back was recessed in, the front is not. 

Or any other idea's with what you would do with this to renew them.

Many Thanks, 

Daryl

[DarylS]

this area took at least 8hours to paint, I split it up though by doing 2hrs after work everynight, because your arm and wrist gets sore trying to contort it into place for all the nooks and crannies. For this one section, one brush sufficed but it was stuffed by the end. I had two more breeze blocks this size and went through 4 brushes in the end. 

[Dave-1]

@DarylS 

Nice work and I like how you broke it down into manageble chunks, I pretty much do the same but if I hit afternoon work after work I know im on a deadline

Dave