I can try
The short version:
you want enough power to stay just behind the crest of a sizable wave, you want ample steerage, and you don't want to have to worry about bashing the prop on the pebbles.
The long version:
(I tried to be brief, but failed...)
Landing in flat or fairly flat seas is easy — burble slowly in to a few pairs of waiting hands and switch off. Equipment makes next to no difference, and it's by far the best and safest way if conditions allow. We always do this if we can.
If it's crashing in though, you want the boat out of the water — if the transom is just far enough away from the water to avoid the next wave (which is partly your own wash), that's nicely judged. If you've not got a winch, it's harder to pull a boat full of water, and even if you have it doesn't do the D-ring at the bows any good.
The way we've always done it is to start your run in from somewhere outside the surf, pick a wave and follow it in just behind the crest. That usually means running in on the plane. Keep the power on as the wave breaks and cut to neutral so that you're going fast enough to carry speed onto the beach but before the prop hits the bottom. With manual tilt and some speed on, the engine will come up with a little assistance from your crew (almost on its own if it's gas assisted), and it won't do it any damage even if the skeg hits the beach. There's probably a one- or two-second interval between cutting the throttle too early (wave over the tramsom) and cutting it too late (bent prop).
At low tide, when the beach dries out to sand with a shallow slope, the technique's a bit different. You can follow a wave in so far, but there comes a point when you need the boat firmly on the plane to minimise its draft — you want to get in as close as possible. So you open the throttle to WOT and punch through the last two or three waves, then cut to neutral at the right moment as usual. You can afford to cut the throttle earlier from that speed, and roll off the throttle a bit more gently if you feel like it. If the boat drops off the plane before it hits the beach, that was probably too slow. In those conditions, it's sometimes a bit all-or-nothing — either take a wave over the back or finish up some considerable distance from the sea.
Having a smaller engine or having power trim/tilt have much the same effect — not enough power when you need it. You need to be able to get enough power into the water to sit just behind the crest and get back there if you slip off the back. If you slip off forwards, you want to be able to power off it and into the back of the one in front. Either way, the result is probably the same — heading for the beach on the front of a wave, which is a Bad Thing. The worst case if it happens is a capsize — it's been done by others before me, and I've nearly done it myself.
The most difficult set-up would be a small engine with power tilt and no power trim (like the surprising SR4). Because it can't tilt the engine with much more than idle throttle, you have to tilt up as much as you dare before the run in, and leave yourself enough time between cutting the throttle and hitting the beach to tilt the engine the rest of the way up. That means that you're committed to having limited power and not much steerage — the perfect recipe for being overtaken by a wave, pushed about sideways and rolled over. Power trim/tilt that works under way is better, but still difficult. More power helps, but not much if you're trimmed up.
More power and an engine tilt system that you can unlock and forget is ideal. That way, you have all the control you need on the run in, and the power immediately available if you need to make corrections. You're less likely to end up a passenger.
Have a 30 on mine, with a 4hp wing, 60 litres of fuel in two tanks, 180kg of P's, anchor chain plus supplies for the day.
We get 18 knots with this rig and it planes from 6 knots within 2 seconds thanks to hydraulic trim tabs. In the chop we get down to 15 knots.
And what a fun and capable looking set-up it is
. And another SR4 surprise (for me): it's possible to squeeze an auxiliary engine neatly alongside the main one, and
have enough space for steering!