Okay, from responses i think i got my answers, through your guys responses.
Just to clarify, i did stop experimenting about 2 months ago, and began being as consistent as possible. i thought i would stick to 1+3 dilutions and saw that 100ml of developer simple enough.

1. If i use the intended amount of developer at current dilution i would have 1L working solution and my negatives would indeed be contrastier as they are currently flat (don't think i would want this)

2/2.5 I guess by not using the full amount of developer, i was not getting Blown Out highlights (correct?).

As for edge data, it is not extremely dark or clear. Looking back through negatives, there's a clear point where you can tell i began to develop 1+3, and looking through them I think it's just my printing which has gotten better throughout this time, along with my improvement in consistency.

While i was at one point wanting extremely contrasty photos, i found this somewhat restricting with 36 photos. The flat negatives i have now are due to exhausted developer.

What i will do is develop 1+1 as mentioned above with a couple of rolls and see how i like that.