Topband: Teflon Sleeving vs Heatshrink for the Homemade FCP

[Jo, YC0LOW]

I am in the process of homebrewing the FCP system for my own station.
I already had three toroids from Amidon, USA, safely, but I forgot to
put the Teflon Sleeveing for the #12 AWG in my purchase order. list.
I tried to contact the Amidon and they are very helpful by already
quoting the price of 55ft teflon tubing plus shipping/handling (with
USPS Priority mail) costs to my address in Indonesia. The amount is
US$ 75 - rather high for a retired person like me :-))
The wire is available here. But, since I cannot find the the Amidon
teflon sleeveing in Jakarta, I wonder if the tubing can be substituted
with other material to isolate the two wires on the toroid, for
example: heatshrink sleeve.
How would it be performing, please?
I'd be gratefull if you could advise to me. Tnx es 73 de Jo, YC0LOW