three questions

I have three questions on my roof please.
1. I have installed a Ubbink tile vent and had to cut the felt to position it and allow the connection piece to access from the rear . Do I need to patch this felt. If so what with? Felt? Or something else?
2. Does anyone have experience with these vents? I am a bit confused on how to ensure a positive connection between the tile vent and connection piece. It only seems to be a push fit and as the tile is already in position it will be difficult to duct tape. Doesn’t seem at all secure.

3. The bathroom fan outlet is 4” diameter and the tile vent connector is 6”. Which is the best way to connect the two? Flexi hose?
http://www.barbourproductsearch.info/ub8-plain-tile-file006366.html[/url]

Whenever i fit a tile vent terminal i connect the hose to the vent spigot prior to finally* installing the tile.

There is a soaker provided with the tile to deal with water run-off.

I use duct tape to help secure the hose.

All the spigots i have seen are 100mm dia.

*for ease, the tile and soaker are fitted first then removed to accommodate the hose.