Slim
We DO treat those ones as VFR. Nevertheless, not everyone can do the approach at the same time....so you still need to apply a degree of 'sequencing' especially when you've got five circuit trainers and the odd vortex wake problem too!
I wish our VFR traffic would 'self regulate' on it's own frequency...I could go hoome early then.
We handle about 85 000 movements per year without a parallel runway and very rarely turn down 'extra' instrument trainers.