Adding weight to the front of the boat is going the wrong direction if you are trying to eliminate excessive porposing. What you want is a LIGHTER front end, not heavier. Porposing is caused when the motor is trying to lift the bow....but can't quite keep it lifted, it is doing a juggling act between plane and plow.
Engine height on the transom, trim angle, prop bite, and raw torque (in that order) are how you diagnose porposing problems.
If you also blow out on sharp turns you may need to drop the engine 1 hole, which will probably cure both the blow out problem AND the porposing.
If it doesn't blow out on turns BUT the only trim angle you can maintain (without porposing) is one that causes the boat to plow, then you either need a better bite at the prop, OR MORE HORSEPOWER. You can have a good prop shop add a bit of cup (lift) to the blades, that will noticably help.
Hydrofoils (IMO) are just a crutch to compensate for poor rigging. And much the same can be said for jackplates.
A properly rigged 115 (turning 5500 rpm) should push you darn close to 50 mph in ANY 17ft. bassboat.