regarding your questions,
1, i have the same problem at the beginning stages of this hobby too.
never install the body when tuning HSN, air flow through the engine is not the same. when u got it constant 230, another 3~5mins richer on HSN would do
make sure u have enough ventilation holes cut especially front and rear. side window is an added bonus during cornering.
2, i think u better leave the idle that way since u dont mention any problem.
on any day, if your engine starts within 2 kicks without u pressing the throttle, its a good idle and LSN setting. try pinch testing before and after u tune it, its a good guideline to start it off with.
hope this helps