Your owners manual will have the exact specs for your bike as well as the method for checking the fluids. The transmission is normally checked cold and on the jiffy stand on a touring model. As for the amount, it will vary slightly depending on how completely the old oil was drained. If I remember correctly the lubricant change spec is 28 ounces for a drain and refill, and 32 ounces for a completely dry trans (initial fill). The proper way to fill it is to start with slightly less than the spec (say 24 ounces for instance), then check with the dipstick and add small amounts until the level is between the Add and Full marks on the dipstick.
This is the trans fluid check procedure per the manual:
Check transmission fluid with the motorcycle at ambient temperature. Inspect transmission dipstick O-ring. Replace if necessary.
1. Park motorcycle on a level surface on jiffy stand.
2. Remove transmission filler plug/dipstick. Wipe dipstick clean.
3. Install filler plug/dipstick until O-ring contacts the case. Do not tighten.
4. Remove filler plug/dipstick. Check lubricant level on dipstick. Proper oil level is between the Add (A) (1) and Full (F) (2) marks.
5. If lubricant level is low, add recommended Harley-Davidson lubricant to bring level to between the A mark and the F marks.
6. Install filler plug/dipstick. Tighten to specification. Torque: 2.8–8.5 N·m (25–75 in-lbs)
Jerry