You wont have any issues using the oko26mm on a 160, pretty much perfect. For the price they are hard to go past. There is also your mikuni round slide, but the ease of tuning the oko gives you is great. 38 pilot jet and a 102 main jet should be spot on jetting wise.
Motoluver, don't forget the Okos' need a longer throttle cable too if you haven't got one, they need 150mm of cable hanging out the end of the outer casing
And get a decent Uni Fllter (48mm i/d) and some spray on foam filter oil for it as well
If not, then this Oko complete set up from DHZ is pretty cheap, might be sold out atm though ?
Ask them for a #38 pilot jet and #102 main jet when you order it too ($5ea)
For street use I'd be going for a round slide, my 190 has a Keihin 28pwk (a genuine oko ) and I wish I'd got the PE. It's just a bit savage off the bottom, round slides don't react like this!!! good fun though!!!!
[edit] This would be perfect with same jets mentioned above!!! (says flat slide, it's not!)