When the rubbers are new they will always seem like they don't fit. It takes a little while for them to obtain the correct form required to both seal correctly and allow the door/boot to operate effectively.
Use adhesive sparingly (I always use superglue every 4-6"), this will allow them to move around and settle to the correct position under pressure from the panel.
Make sure the channel is COMPLETELY free of any old rubber or glue as this will hold the rubber higher than desired.
Be aware that the Rares door rubbers don't have any moulded areas around the top half of the door aperture, this is really an issue in two places, half way up the 'A' pillar where the guard/door/cowl meets, and half way up the 'B' pillar where the stop or bump rubber is.
At the 'A' pillar, splice in a different profile rubber that more closely matches the original profile - the Rares rubbers (and all others) don't have the right profile here and will always give problems - either by preventing the door closing properly or by rising above the body panels when the door is shut. The look of plenty of nice restored cars I've seen get ruined by this piece of rubber sitting proud.
(I don't have a picture of this area - possibly someone could post one?)
At the 'B' pillar, you'll need to cut a 'V' shape into the back of the rubber and glue it so it is tighter where the door is trying to shut at the change in angle on the 'B' pillar, just above the bump rubber in this photo
This is a NOS rubber I fitted but it clearly shows the desired profile. The Rares rubber sits very high here and will definitely stop the door closing properly.
If you a fully restoring a car Julius from the ACT club recommended slightly widening the door channel that the rubber sits in - this would allow the rubber to expand outwards under pressure from the door and seems like a very valid idea.
I have a new NOS boot rubber in my sedan and while it fits good in the channel its only marginally better than the Rares one.
Correcting ill fitting boot rubbers could be approached in the same way, widening the channel or at least adjusting the channel slightly downwards.
Another guy that does GT Falcons told me that he puts the rubbers in, lubes them up good, then adjusts the door striker/catch so he has to really slam the door. Leaves it for a few weeks, the rubber is set to shape, re-adjusts the door out slightly, and all is well. Another good tip.
You can get anyone's rubbers to fit, none of them fit out of the packet, just be patient and whatever you do, don't use contact adhesive!!!
Cheers,
Craig.