Right ive brought some fuchs silkolene fork oil medium SAE 10 would this be fine for my fzr or not?

I have the same oil in my Genesis forks and have had no adverse affects.

Just done the fork seals on my trackbike with the same oil. Works brilliantly!!

How much did you put in???

standard amounts of oil are

for the 3TJ RR
509ml of oil (10wt) with 80mm air gap, with no springs and the tube compressed

for the 3TJ SPs
433ml of oil (10 wt) with 106mm air gap, etc,etc

good starting points, then fettle too suit