Quite simply tabs whether affixed to the back of the transom or fins put off the lower unit of the OB, add lift to the rear of the boat. This lift, however, is actually created as a result of 'drag' and various designs are better at minimizing the drag than others.
For such a small boat, I'd go with a fin off the OB lower unit, but not on the 4hp. For small tins where the bow rises uncomfortably while planing out I've always used the hydrofoil fins; some are really great and some work, but at a huge decrease in speed.
The better OB-foil designs optimize speed and make the hull really perform, at least by my actual testing (my boat club has a fleet of a few dozen small boats and I help manage the boats, motors and docks). A larger hull could use those Smart Tabs. See these posts for more info on both types:
https://forum.tinboats.net/viewtopic.php?f=4&t=40090
https://forum.tinboats.net/viewtopic.php?f=3&t=39462