For tip lights I use the actual piece of the tip that I cut out as the mould.

I add a little 1/8 balsa to the piece because as you mould them the plastic
tucks under the mould.

The mould fits in a vice on the supporting stick. The plastic is sandwiched between
some scrap wood pinned through the plastic. You just need the wood on either side
of the plastic, not all the way round.

Heat the plastic in front of an electric bar heater until it gets floppy then quickly
stretch it over the mould. Once it cools trim to shape & fit.

If you need them tinted Tamiya makes paint for plastic models called ''clear red'' &
''clear green''. - John.