In my opinion high pressure small injector vs low pressure big injector you still end up a similar flow rate. The hardest part is knowing how much injector/pressure is needed for your particular build. I too had problems with one of those "18psi" springs coil binding at 17psi causing fluctuations. I went with a 94-95 BBC spring thats good for 30psi (thanks Dave) and 305 injectors @22psi to get the flow rate I needed. The key I believe is after finding that magic flow rate you need is to find a spring that can achieve that desired pressure easily and consistently, then you can finally tune from there. I spent a lot of time tuning around that coil bound spring chasing my tale trying to sort out a VE table and other issues. With my current setup I had to start over completely with a fresh bin because I had so many things changed chasing my fuel problem.