Husky 250 jetting request for help

Posting a PM from new member, can anyone help him with his jetting questions?

I talked at you a little while back about my 250.
I've been reading and reading this site...and I see alot of amazing knowledge being shared about the bigger bore vintage husky's, and that's awesome.
I wish there was a little more talk about the 250's, as I am dying to get out there and ride it again.
(hadn't since I was 16, 36 now) Anyway..back in the day...a local guy(northern british columbia canada)
offered up a mikuni for my bike, saying it would run much better. back then I didn't know enough about anything to make it run correctly, but I have torn it down, inspected it, reassembled and resealed it,and got it going. and ridden it, and it ran surprisingly well! it had been probably 15 years since I rode a two stroke and just loved it. problem is...I cannot get a reliable run out of it...I am having a major flood out problem once I get it up to operating temperture,
as well as general weirdness with plug readings. I feel I am totally out to lunch with the whole carb setup. It's a 36mm mikuni, and it's a 73' 250.
Is the whole carb just too big for the 250? to much air flow? man, it seemed to run great and really pull a few times that I had it going good. what would a basic main jet size be for a pre-reed 2 stroke such as this? would anything over 300 be out of the ordinary? the carb had a 280, which I changed out to a 320 and it seemed to get rid of a bit of the missing at flat out. I have downloaded the Sudco, and VM super tuning manuals and have gone through them both and understand all the principles and staging of the sequence of events and parts through the power range.....what I am looking for is a baseline to start from...something that would have been kind of converted from the old Bing settings to approx the same flow and fuel for the mikuni.
180 main? 200? 300? really out to lunch here...and the flooding thing...man.......it's like...it runs great for 15 minutes till hot...then I will go to come off a high speed run and it's like someone pours a full cup of fuel right into my cylinder....I tear off the air filter...and I can literally see the blue-green fuel just tumbling around in the air bell....LOTS of it.....it's driving me crazy! when I turn the carb upside down to check the float height....the hinge-plate thing the floats hit....sits perpindiular to the bowl mating surface....I've been told this is generally the height give or take a few milimetres. I want to just run this baby a little on the rich side for longevity and ride her! (by the way, I am running what used to be a KDX 175 airbox, with a good uni-filter. I trust this setup...as I spent alot of time eyeballing it, and getting everything fitting and sealing right, even with taking it off 10 times a day. good fasteners in good places, clamps etc. So I am trusting that.
Any tips on baseline jetting for 250s with mikunis? I'm dyin here! Thanks alot for your time.
Garth