Do a lot of leg raising , don't even thrust your heel out , just raise your leg on the centreline straight from your stance . Make sure your knee is coming up to the elbows of your guard so groin is protected and there is no gap in the midsection.
Alternate from leg to leg , trying to relax the hip joint as much as possible , pivot on the support foot while raising , look in the mirror to see that shoulder movement is minimised , from side make sure back stays straight , a common mistake is for people to hunch forward.
When you are doing chi sau , you and your partner can practice planting close range thrust kicks into each others gut. Just bring your knee up high and into your chest and thrust out with the heel.
While you are doing chi sau , practice moving forward and doing left and right low heel kicks to the partners legs as he is going back , or even alternate them with hook kicks to the outside and inside of his thighs.
It is important that you still keep the forward force on in your arms , the tendency is for people to slack off with their arms once they start doing stuff with their legs , this is not good , it will indicate to an opponent that something is on its way.
I tried the ankle weight thing years ago , to be honest It didn't do much more than have a slight aerobic effect. Probably wouldn't hurt to use them with leg raising or holding your leg up for time in a guarding stance .
But I would be wary of doing full power kicks in the air with them on or even without them on , I think its a great way to damage cartilage. Legs have more mass than an arm and you need something to impact with to decelerate the kick.
The thing you are doing with the piece of wood is good , just getting that mind body connection happening by stamping down with your knee. Be careful that you are sunk down in your stance , don't let hips unlock , back straight , let the weight of your leg do the work and stay relaxed.
You can practice ' Trap Kicking ' have a partner hold their arm out like they have just thrown a punch and you practice kicking at different targets on them with various kicks at the same time as you latch (grab) down on the arm .
Work single and multiple kicks , and make sure you work all the different configurations such as latching from the outside of his arm , inside of his arm and also grabbing his arm with both your hands. You are using the partner a bit like a wooden dummy . When you are grabbing with one hand make sure the other hand is in Wu Sau guarding your face.
If I recall correctly you have a wooden dummy , so you can practice the same thing on that or just practice kicking from low to medium height and vice versa on the dummy.
For power training you need to kick a heavy bag that can be raised and lowered so you can train your medium and low heel kicks , hook kicks etc.
Or you can take the bag down and stand it in a corner and work on your low kicks like that.
Or a 3 sectional wall bag is also good , but even better is a partner holding a kick shield as they can give you feed back and move around so that you constantly have to re adjust your stance and work on your different ranges.
Another one that I like to do on the heavy bag or hand held kick shield is to just stay on one leg and keep the leg in the air and just keep kicking the bag or pad without grounding the leg . Its great for balance and the stance and is surprisingly tough on the legs and cardio conditioning.
This exercise is good for developing the hip action that is needed for powerful kicking. Get up close to the heavy bag or kick shield , raise a knee , keep it about an inch or two from the pad , and using your hips project your knee into the pad .
Don't overdo it , it is only a very minimal movement and could quite easily become a committed movement if performed incorrectly , once you have worked on that for a while and happy with it you can then start using this small hip projection when you kick , making sure to time it properly with the impact.
If you don't have any equipment at home or someone to hold the pad .
I've heard of people that have cut a car tyre in half , cut three flaps at the ends of the tyres , and bolted the tyre halves to the wall or a tree by putting bolts through the flaps.
Put one at medium height for your higher kicks and one just off the floor for your knee / shin height kicks.
Don't forget to keep up your supplementary training like the SLT form and still practice your pivoting , these work on your foundation and help you to find the centre of your body so that you develop your balance.
The main thing is the stance , you could have faster legs than Bruce Lee but if you are unlocking at the hips and too high in your stance you will not be maximising the power of your kicks and force will be leaking off somewhere.
Don't use any brute strength stay relaxed and only tense your ankle just before impact also being careful to pull the toes back and drive through with the heel so your force penetrates through the pad.
When you are training solo it is important that you stay self conscious of yourself in regard to your stance it is easy to get lazy when there isn't a Sifu telling you to relax and sink down , so you have to be your own Sifu and be critical of yourself.