could somebody please explain to me exactly how you would use an attenuator set to load and 2 amps for amp slaving and if wattages for both amps have to be the same and any dangers to look out for. fed up with sucked attenuator tones or thin master volume tones due to volume being on 2.

for pubs and clubs btw.
It depends on the attenuator, but usually you'd turn up to max attenuation, then use the line out from the attenuator into the effects loop return on the second amp. Wattage doesn't matter as long as the attenuator can handle the entire output of the first amp. Dangers to look for would be overheating or using an attenuator that doesn't load properly without a cab connected.

For what it's worth I've found that this is often not any better than just turning the master down on a decently designed amp.
parts express sells 4 or 8 ohm 200w loads for 30$ or som just get 2 of those, and mount them in a box and put jacks in it. this would allow u to play without speakers, then you could use a behringer di with cab simulation or a h&k redbox right to the board. check thwm out. ull want the max wattage.