what you got here is an old style engine and alternator/generator,and a modern panel,so the tacho sender may not work with the vetus guage.
but assuming the sender is an interupter type this may work.
from the back of guage to yanmar wiring tree.
i am assuming you have the battery
connected to engine ground,and engine pos+ on the starter motor.
(ground terminal to black wire AND orange wire (to engine ground and battery
negative and panel neg)
middle terminal to blue wire.
b+ terminalto red wire.(via on /off switch,ampmeter and pos supply to panel)
(it may be that it works in the opposite direction,so your blue stays in the middle,but the orange goes to the ground,and b+red wire to neg side of on off switch) (it may also not work with this thype of guage,as according to the wiring diagram there is an exciter circuit to the sender when the starter button is pressed!!!)
,the oil sender is only (on /off) not a pressure sender,blue/white wire.
this will work with the indicator light,but not the guage.
water temp will give a reading,but not nessacarily the correct one if impedences are not matched ,,brown wire to "S" on back of guage.
might be worh getting new compatible senders and guages for temp and pressure.
amp guage, red wire from engine to + on guage ,-minus on guage to red wire to on /off switch.
field wire ,(white and red wire) to red indicator light,then to neg side of on/off switch.
this should work but it might be easier to find the correct panel on ebay.co.uk,lots of parted out ysb/ysm engines over here.