Thought I'd chime in on the carb set up, since I swapped my '88 over to a pair of Mikunis last summer (with lots of remote help and a custom-made cable bracket from Gerhard).
I found a connected pair from a mid-90s SS900 on ebay for ridiculously cheap ($60USD) a couple years ago. I fit them with a Dynajet stage 3 kit for the SS, because I installed K&N pod filters (P/N SN-2530) and I already had a pair of Cobra F1 exhaust cans on there (and they're pretty free-breathing). The connected pair simplified the set up in that I could use the throttle tube from a Monster/SS & that bike's stock twin-cable set up, as well as replicate that fueling process:
I ditched the Paso's stock electric fuel pump in favor of the Mikuni vacuum-fed pump from a Monster, and I routed the fueling from tank > filter (canister-type from a Monster, left side of bike) > fuel pump > carbs. I mounted the vacuum pump on the right side of the bike (clutch side) in a V in the frame, and 'power' it from the nearest intake manifold.
I swapped the manifolds for a pair from a SS as well; I wound up with a pair from a 900, which are slightly longer than the pair from a 750, which twist the carbs slightly, but that's a non-issue. Actually, I was happier with that, because I think made more room for the pod air filters.
While I obviously ditched the airbox, I kept the crankcase breather box, which lives right in front of the battery, under a short frame cross-member. That previously fed the Weber's airbox, so I wound up installing a
small K&N crankcase breather filter instead. That's secured to the frame, towards the front of the bike on the left side.
I also added the triangular 'null air' box from a Monster/SS, which fits nicely into one of the upper V's in the frame (right side) into which the carbs 'breathe'. You'll see the set up in any pre-99 Monster/SS parts explosion. Each carb has an air line (with a one-way valve?) that blows into a grey plastic box.
Besides the K&N items, 2 new throttle cables, air/fuel lines, fuel filter, intake gaiters and necessary clamps - everything was picked up from ebay and shops like ducpower/guzzitech. The air filters I found cheapest on Amazon; the cables, fuel filter & intake gaiters came from Ducati. All told I think I spend under $150USD, and several hours horsing around.
And the bike is
transformed. I tried a number of alternatives with the Weber, although admittedly not the solution Jon has detailed

but I'm extremely satisfied now. The bike has never run this well. Starts like a champ, warms up quickly, idles comfortably around 900-1000 and pulls hard everywhere with no stutters or plateaus.