I would drill if you (or dad) are confident enough;
Many videos on you who or whatever but if you are going salty then you should learn about BRS(bulk reef supply)
How to Drill and Aquarium and install an Internal Overflow - Bulk Reef Supply
I have used CPR overflows with the Toms aqualifter(still use one on my 29).
Get one of the largest overflows if that is route chosen.
The overflow is the main limit to amount of flow a system can handle.
If your flow is low it will not be a problem,but if you want more flow then the overflow can handle... then disaster.
Reef octopus also makes decent overflows.
The advantage of a sump over a canister is not even comparable.
Much more room for media if you choose and the ability to hide things like heaters,reactors,refugiums,protien skimmers(<THIS!).
You will want a protein skimmer and the better ones run in sump not HOB
,but this may be next topic after filter and lights!
Hope you and your dad enjoy.