Hello and welcome!

From what I understand about the MTL jumper manual, S1 does set the CPU multiplier and FSB speed.

For the CPU multiplier, from S1/1 to S1/3 is used to configure the CPU multiplier:

1      S1/1 S1/2 S1/3
22.0x:   On  Off  Off
32.5x:   On   On  Off
43.0x:  Off   On  Off
53.5x:  Off  Off  Off
64.0x:   On   On   On
75.0x:  Off   On   On

There are two remaining combinations for 4.5x and 5.5x multipliers, the former one displayed on the manual is the same as 4.0x which is incorrect.

S1/4 to S1/6 are the ones that sets the FSB speed:

1        S1/4 S1/5 S1/6
260 MHz:  Off   On   On
366 MHz:   On  Off   On
475 MHz:  Off   On  Off

More FSB speeds can be achieved with five remaining combinations, but I don't know exactly which PLL clock generator uses, so I can't help further.

According to jumper manual on TheRetroWeb (for FSB 75MHz, and multiplier 2x) dip switches should be set as following:

S1/1 - on,
S1/2 - off,
S1/3 - off,
S1/4 - off,
S1/5 - on,
S1/5 - off

Edit:
@Gmlb256 sorry, you already wrote it... 😀

You could just set your multiplier to 2.5x and try setting the jumpers to every available combination (there are only 8 combinations)

Record the result. You might have some very high or very low FSBs that don’t work.

You could also take a clear closeup of the clockgen / PLL area and post it.

If I had to venture a guess On On On is probably 50mhz, off off off is probably a high frequency.

Thanks for the help guys I ended up getting it to work. I probably figured this out ages ago but I didn't realize the BIOS doesn't show higher than 400MHz (even though it is).

For anyone that finds this in the future it ended up being;

S/1 On
S/2 Off
S/3 Off
S/4 On
S/5 Off
S/6 Off