Hi Gavin ,
Tip wrap happens when leader is to thick or knot is too bulky for a particular size of tip top guide , a momentarily snag caused by leader or knot at the tip causes the PE line to overtake it and cause the tip wrap , pretty much the same as wrap on the stripper guide . To remedy this , use thinner leader n smaller knot .
On the silicon spray , I dont take any chances , I use the silicon spray from the PE line manufacturer , have 1 can which have lasted me for 3 years and still some in it . Not much to spray , only a few meters suffice .
Best regards : Jon .