IMHO the simplest and cheapest way would be to get the kit from Red for the RS36's.. bolt on all the work done. Instant improvement on performance, response and gas mileage, lighter throttle and such.
If you find a used set of Mikuni's RS36 then you still need to refurb them before you set adapting them to your bike and getting correct jets etc.. hence why again IMHO the above is the path of least resistance.
Add up the parts to refurb and old set of Dells with new slides emulsion tubes needles etc is getting up there also.
CV's are also an option but you still need to play around and do some cutting and shutting and again they are used so will need to be refurbed then also limited on the jetting available etc so cheap may not end up that way.
Now with the new Dellortos that I have looked into ( in 36 anywho as that is what am looking for ) as others have already said need to be drilled and tapped for the mounting plate ( doable ) then you need to do away with the idle speed screw... oh and seems the only PHF's I can find in silver are the DD1 Cant find the other side. There are sets in black though which by the time you purchase and then play around with will get you near the price of the mikuni kits. If someone can tell me otherwise great as I have a new set of towers ( NOS ) just waiting for a set of new 36 Dells for the Corsa.
I have gone another route ( as I like a challenge ) on the RGS and Cico .........still finessing and do plan to do a write up at some stage
once am happy with both sets but again the route I took is not for the faint hearted
Other option is fuel injection