Reddiseals do glazing bar tape in various sizes.
I use the same width tape as the bar, although I believe some joiners use a narrower tape and do a thin bead if silicone after. If you use narrower tape and leave the gap it fills with carp eventually.
The glass has to be cleaned before application and the bars cant be over length or sometimes the foam tape doesnt bond and once water gets behind the bar comes off. Mumford and Wood used to use butyl tape, so they must have that works better for them. Would be a nightmare to get the bars off though.
Duplex bars I find are not very accurately positioned so tend to order 18mm for a 22mm glazing bar.
The bars I make in accoya. I used to use composite foam board but it expands too much. Q wood make a composite plastic / wood bar, but it would need to match your moulding. Solid timber bars are best avoided. For oak jobs, I have to select really mild straight grained stock -using any old off cuts with rubbish grain is best avoided. I think natural finish glazing bars are a wrong detail anyway.