LG RZ43PX11 - getting rid of sparklies by adjusting v up and V down

[Cornboats]

I've had to change y-sus and Z sus boards now sets got sparklies all over like a rash.

I read previous threads and consensus  appears to adjust v-up and v down pots. I read in the manual that this could only be done using a scope.  My scopes only 20 mhz. Anyone done this successfully. Is it just a case of fine adjustment a bit at a time. Do you move both pots in the same direction or 1 at a time?