Yep, to richen the main needle you need to turn it anti-clockwise (which winds it out). Its the same for the low-speed needle (which is the screw that`s set in the slide of the carb).
My suggestion would be to richen the main needle one turn from its current setting, then see how its starts/runs, and then work from this setting to fine-tune it. It may need more richening than one turn though, so it may take a bit of experimenting to get it right.
One hint that may be helpful, is wind the main needle all the way in (anti-clockwise), whilst doing this, count how many turns it has taken before the needle stops. Keep a note of this and then wind out the needle back to where you began. You can now use this as a reference point as to where the bad tune was, and richen from this setting accordingly.
Once you have it tuned and running well, again wind the main needle in and count how many turns it took.....keep a note of this setting for future.
Remember, tune will vary with weather conditions, so it will need slight tuning adjustments as things such as temperature, humidity, change of fuel type etc will all affect engine tune.