Mixers and injection put differnt demands on the liquid side of the system. As you are on mixers 8mm feed pipe T'd off to two 6mm lines to each R90 will work fine. The issue you might have is with the Multivalve, ideally you want a high flow 8mm valve but might get away with a standard valve adapted to 8mm. With a 4 hole tank the BFC (service) outlet valve is the one to use. If you were on Injection 8mm line could be marginal and the best bet would be twin tanks with twin 8mm lines.
The biggest problem you will have is getting a decent idle as the air speed stalls at lower revs on each cylinder. You will want the older model R90's with the spring on the idle screw as the later ones without the spring struggle to allow enough fuel through on idle
thank you CS, i have two r90's , identical to each other . the sensitivity screw has a spring , the tickover bleed has no spring ...pooh!??
i'm guessing , but i wonder , if tickover is a problem , whether i can modify the bleed screw ti to allow greater bypass.
i have ordered all my connectors , so they should be here this week hopefully . i have made the tank mount , and buffed up the 90's a bit .
now i am trying to design a good method of connecting the vaps to the mixers , 6 per vap.
i have various options , one is a 22mm copper rail with all the mixers into it equidistant . and the vap into it with both feeds spaced appropriately for best distribution .
next is a 3 into 1 manifold , one for each vap outlet ,then 3cyl per manifold .ideally connecting them fujrthest pulse away ,so 1/6...2/3...4/5..
my favourite , is a vessel , with feed in the bottom ,and snaky 6 pipes out the head .so its got a medusa theme , but im worried about response time , transients would theoretically suffer with a greater dampening reservoir . i don't know if this is a real problem .
oh by the way chaps ,thanks again for the positive reaction , most encouraging