Hello. First, a calendar view is available, but is optional. You can also give a list view... or you can create direct links to registration manually or using our EventLink plugin to place Register buttons in an article or other places.
Second, using our powerful fields, you can give various scheduling options... in this case you'd use checkboxes, radio buttons or dropdowns (depending on if you want to allow people to select multiple slots or not) which will give the times like 8:00, 8:20, 8:40, etc. You can set fees on each time (if needed) so price is calculated based on which slot is chosen or how many are chosen... you can also set a limit on each slot to make sure not more than 4 (in your example) people select that slot. No other solution will give you all of that control in your fields.
Third, you can have a field (or fields) to select registration types... to give the different prices for guests, participants, etc. We also have conditional fields (not available elsewhere) so you could set (for example) the time slot options to show up only if someone chooses to register as a participant. If they choose to register as a guest, then you could have different options to show up for meal type choices, etc.
DT Register can get the job done
If you have other questions, let us know. Thanks.