What you need to do is open the idle feeds in the metering block up .002 . Not that hard to do but you need a pin vise and wire drills. Barry Grant has a nice kit, Jegs sells it. The idle air bleeds might need to go down as well. They may be like .073, I would try .68 Now thats not as easy
The HP..and most all Demons..have removable air bleeds but on your carb, the bleeds need to be expoy or tap for air bleeds. A carb shop can do it.
Many carbs have no choke. Mine does not but once its set up right, I wait 1 min. max before backing out of the garage and taking off, easy of course until the motor warms up. But then I keep the exhaust heat on the intake open, thats a big help too. Funny, I have no heat problems in the summer time either.