I use LV to indicate a light value - a measure of the intensity of the light in the scene. It is film independent.
EI is a measure of the light sensitivity of the system, including factors like the film, the meter, the camera equipment, your metering technique, your preferences with respect to shadow detail (in the case of negatives) and, to a certain relatively small extent, the developer you are using.
The ISO is a measure of the light sensitivity of the film when measured under very specific, repeatable circumstances - those circumstances will most likely be at least slightly different then yours. The ISO rating allows you to compare films from different manufacturers.
When it comes to developing times, within a reasonable range, they have relatively little effect on shadow detail. They have a relatively large effect on contrast.
In the pinhole world, you are often working at light levels (at the film plane) where reciprocity fails. As a result, it is not uncommon to have the shadows record on the film with much, much less density than the highlights. The difference between the shadow density and the highlight density is much greater then when the light levels all around are much higher (at the film plane). As a result, the overall contrast of the negative may be increased. This may lead you to decrease development time, to tame that contrast. But you may prefer not to make that change.
If you experiment with different ratings, you are essentially experimenting with different ways of interpreting the information from your meter, in light of the behaviour of your system (including the film). Your goal is to get the right density in various parts of your negatives, but you are concentrating particularly on the shadow densities.
If you experiment with different development times, you are essentially adjusting the contrast between the densities which record the different parts of the scene, while concentrating particularly on the highlight densities.
Hope this helps.