Certainly help yourself to a first project. But our advice is to stick to low power levels at first. This is simply to protect you from burning out all kinds of stuff and becoming discouraged.

Consider a few points you should have learned in your reading.

If you make a 1.3kW supply, the currents involved will be 20 times more than in a 65-watt supply, all other things equal. Resistive power losses, which create heat, given by P = I^2R, will be 400 times higher, unless you can reduce R by say 50x, so the loss will only be 8x higher. But reducing R by 50x means the gate switching capacitance of the large power FETs will be 50x higher, leading to all kinds of problems, compounded by a need to switch faster.

Recall that every time you switch a current you create an inductive voltage spike, given by V = L dI/dt. When you make a 1.3kW supply its dI term is 20 times more than a 65-watt supply, all other things equal. Furthermore, with high capacitance FETs and large currents being switched, you'll learn about switching losses and the need to reduce switching times in large power supplies. This means dt must be smaller, say 10x faster than you could safely get away with in a 65W supply. Therefore the V = L dI/dt formula tells us the induced inductive spikes will be 200x larger in a hypothetical 1.3kW supply.

For example, a 12V battery powering a 1.3kW supply. In an H-bridge we'll be switching more than 108 amps. We determine that to protect our FETs they have to switch in 30ns. That's 3.56 x 10^9 A/s. Now, if our FETs have 25nH of total source-lead inductance, which is very little and requires effort to achieve, the source-voltage spike will be 89 volts. Which far exceeds the 20V gate-voltage failure limit.

The way you'll experience this is that the converter may work fine at low load levels, but as you turn up the power, it'll suddenly fail. No doubt with substantial explosive accompaniment. When you look to find the part failure, you'll discover there are many failed parts, because as one fails it takes out others, making it hard to determine the exact failure sequence.

Our advice is to start out at low power levels and learn as you go.