I ended up quickly deciding to use the 50mm 1/8 lens, as I could focus the shot without the filter and then put the filter back onto the lens without accidentally changing the focus, where as with the 35-70 mm lens I had originally planned on using, it is way too easy to accidentally move the focus when trying to put the filter back on.
I used a spotmeter and metered at ISO 6 for the shadows on most shots, as I'd read this as recommended when using the R72 filter to account for the amount of light the filter cuts out. Next time I will meter for the mid-tones at ISO 6 and do a comparison, as looking at the negatives everything was a bit over exposed.
Out of the roll of 36 shots, I was pretty happy with about 5, and the rest, whilst moderately happy, I will take as a learning for future. The main one being to keep the frame as simple as possible. What looks great to what the eye can see can just become a mess when shot in infrared.
The other learning is focus, everything seems to be just slightly off, but really only noticeable once you zoom in to the scans. I will do some more experimenting with the next roll of film ... fingers crossed for a nice sunny winters weekend soon.