For others with the same challenge – I ended up with this. Not pretty, but it works – at thats just fine sometimes
<?php while ( have_posts() ) : the_post(); ?>
<?php
global $post;
if ( $post->ID == ('insert_own_ID_numberof_post')) {; //e.g. '75'
wc_get_template_part( 'content', 'single-product-onepager' );
} else {
wc_get_template_part( 'content', 'single-product' ); } ?>
<?php endwhile; // end of the loop. ?>
…all i can say is – dont use: ‘Hotlinked Image Caching’ plug-in.
Try another one