Advice for DIYer using Krend

I've built a small garden wall using 7Kn blocks and want to render it and am thinking of using Krend (ye don't laugh) or Weber. I like the idea of using a coloured render (rather than sand and cement) since I don't want mess about painting it every couple of years. Im thinking of using white and scraping it.

Would appreciate any advice on the following questions:-

1. The blocks are dense but is it good practise to use some sealer or primer on the blocks first before...

Advice for DIYer using Krend