Yes, you can choose time slots, and amend the length of time for scheduled calls with LimeCall.
Personal / User time slot settings
Go to Settings > Personal > Working Hours
Company level time slot
Go to Settings > Company > Business hours
Selecting time slot intervals for scheduled calls or meetings
Go to Settings > Platform > Schedules
Here you can amend the following:
Time Slot Intervals
Intervals between time slots where customers can choose to schedule calls.
Minimum Notice Time
Limit the number of calls allowed for each time shot
Schedule Buffer Time
Buffer time before a call can be scheduled, allowing sufficient time to prepare for calls.