Should E-61 rotary pump owners try to replicate the 6-12 second dwell time produced by vibe pump E-61 machines?

I've read that the middle position is only useful for plumbed in machines because the middle position does not do anything on non plumb machines. I believe this is still true; however, I have not seen any discussion on the "just beyond middle" position. Is there any benefit in using this position to preinfuse?

In this position I get water flow without the pump engaging, but the brew gauge registers no pressure. I'm interested if anyone has experimented with using the beyond the middle lever position. Were you able to see achieve full puck saturation within a reasonable time before you engaged the pump?

*edited for clarity.

My experience has been that if you hold that position with no pf engaged, it will run out of water shortly and turn to steam. This is one way to heat the group fast. It's a weird thing that happens. Maybe with a puck it won't run out before saturating the puck, but I don't think you'll get full saturation.

I think the best thing would be to split the input to the group with a solenoid into a flow controlled pipe, and then be able to switch it with a button back to the normal flow (slayer). This could be done very cheaply.

No.

You need positive pressure to preinfuse. Even if you let the thermal expansion of that just past mid position spit water into your puck there will not be enough pressure to get any real pre infusion. The only way to really get preinfusion on a rotary machine is to plumb it in, set your input pressure at around 3bar and add a delay on make relay to delay the pump kicking in. However, I doubt you will find any improvement in your shots after going through all the work.

I don't know E61 machines at all, but I would guess that it could be designed such that the pump came on just before the valve opens (ie, no middle position). With that, it would be possible to use a slightly opened valve as a restrictor to modulate down pressure, even without plumb-in.

I believe that preinfusion and/or slow pressure ramps are beneficial.