WG setup for Twins

[Jerred]

I have been running my twins for a few months now, including a 4600 mile move to Alaska with a 13.5k# travel trailer in tow. They work fine, but...

Top= Bell Turbo USB#4 custom, by Pius Erbele
Bottom= BHT3B, PDR modified with 26cm housing
WG= Tial 38mm with 1bar spring between the manifold and the hot pipe.
note: I custom fabed all the plumbing myself. I had to remove the WG from the USB and block the WG valves with a plate and two bolts. I have the 1bar spring in the Tial WG and a regulator plumbed in to the bottom of the spring to take boost air from the top turbo outlet to be able to adjust when the WG dumps.

I can make 70# plus with h2o meth, no sweat, a little laggy, but not bad for twins. I have both the manifold and the cold pipe in between the two turbos plumbed with a boost guage. At 50psi of manifold boost, the boost guage for the lower turbo reads about 15 psi. That's at a constant 50psi at the manifold and both pressures are constant. I had tried a .5 bar spring and was getting almost 35psi of boost from the lower turbo at 65psi at the manifold which seemed too high, and very laggy. Running on the dyno, it was like a coal fired train until the HT3B spooled. When I put in the 1bar spring, it got better, but I don't think the bottom turbo is doing enough work. If I open the regulator to put some air under the spring and open it sooner, it just gets more laggy, not letting the USB spool enough to get off the line. I'm thinking I need to combine the two springs to hold the WG closed hard, and then adjust the regulated air to the bottom of the WG spring to open it when the USB is pushing about 20psi, and then dump the rest of the exh air while keeping the USB spooled at a constant 20psi or so, but I don't know how to control that since I can't measure the USB's output.

Anyone with a similar setup have any ideas? Unfortunately, I live on an Island in Alaska and don't have access to a dyno, unless I hop the ferry to Anchorage!!