Hi
On the Rollei use a dark opaque filter not the 25, I shot a roll at the Botanic Gardens a couple of weeks ago, to lazy to take the tripod, Stan is right with the 6 maybe even 8, I change my film with just a jumper over the camera, make sure your wife is with you, or you will get strange looks, the colour infrared has to be complete darkness, B&W seems to handle a little bit of the light.

I don't really know that the SFX film is really infrared.

Whatever you do be patient, and use a tripod, and write down every setting of every image, that way you know where you have gone wrong, or where it went right.

Regards
David