Inverter Power PCB Layout considerations

I have been curious about proper Power Inverter and VFD PCB design for a while now.
The first PCB I had made lasted about 10 minutes as I was stupid enough to place the IGBTs and Driver ICs on different PCBs.
After that I did research and I now understand the saying 'Layout is critical to reliable operation of power circuits. Please, give it the necessary attention!'
I now understand the basics such as keeping AC and DC loop inductance as small as possible. The driver should be as close as possible to the switches and so on.
I would like some sample layouts so that I get important facts right such as:
1) Whether to use single sided or whether double sided PCB is a must?
2) Do I place the switches in-line or in the way they are shown in the circuit diagram?
These are just a 2 examples of questions in my head right now.
I feel that if someone could give some tips and/or show me a sample layout, I will save a lot of time rather than continuing with trial and error and ending up with something inferior to what is the standard way of doing it.

Double sided, at the very least. Depending on the power density, multilayer boards could be mandatory.

Also, the copper thickness cannot be the hobby-grade 0.5 oz/ft2. Again, depending on the power density, I've seen boards where the power layers have been plated 4 oz/ft2 or even larger.

Should I place all switches in line or some other way?
In my previous design, I got large voltage spikes during switching. I had the DC bus at 12 volt and my spikes were upto 40-50 volts peak to peak. Would adding a decoupling/bypass cap next to each half bridge solve this? If so, what value and type of capacitor to use? Is a 1uF 400V polyester cap ok for the dc bus at 325V?

As you can see the first file, it is being used as a simple square wave inverter with +12V and -12V outputs. The DC bus is at 12V. The voltage spikes are about 60V in either direction making it 120V peak to peak.

Similar spikes are in the second figure in which it is being operated as a bipolar SPWM inverter. The figure shows the Voltage and current waveforms respectively for inductive load.

I need someone to please confirm that this is caused by DC and AC loop inductances and I should get a good output by improving the layout and adding decoupling capacitors next to each half bridge.

My major question is which kind of capacitor and value and voltage rating can I use. I have bought 3 1uF 400V Polyester caps from a local shop. Can I directly connect them near each half bridge without any Resistance as bypass caps without anything going up in smoke?