Questions about the Matchless DC30 Effects Loop and Phase Inverter

[psychepool]

hello.
I'm planning a Matchless DC30 clone.

What was most perplexing when I looked at the circuit was that a separate effects loop was assigned to each channel.
I think this is probably because the preamplifier channels are input into separate grids from the phase inverter.

I'm not sure if FX Loop is that useful for this type of amplifier. I'm thinking about just skipping it.
If I install the FX Loop with the same configuration as the original amplifier, it would be very inconvenient to have to change the send/return cable every time you change the channel.
If the part leading from preamplifier - fx loop - phase inverter is configured as follows, will there be a big difference from the original amplifier?

channel_loop.jpg

Additionally, I have a question about the effectiveness of FX Loop.
The Loop of this amplifier is a passive loop.
If I increase the volume of the preamplifier, the loop effect will obviously not work properly. Is it okay to not install an active loop circuit?

And this amplifier seems to have a type of circuit that produces more distortion from the phase inverter/power amplifier than from the preamplifier.
On this amp, is there much difference between connecting effects such as delay to the FX Loop and connecting it to the preamp input?