What I maybe missed in all that is what is the expected size od cleaved and uncleaved? You mentioned 150 and 270+ bands, is it the expected size? Or rather expected size with a double band (if so, what is the bp difference between the double band).
So is the ONLY problem there the diffuse bands?
In paper mentioned, I so only one gell picture and it's pretty crappy if you ask me, it would need much better resolving and misses a marker completely. So reason why theirs is not diffuse is they didn't run it such long.
For samples with very short fragments (150 would count in that, especially if they are after restriction) I found better to use SB buffer. It can run on much higher voltage (at least 1/3 higher) and thus the small band do not diffuse that much. One catch though, it doesn't work well with high-salt samples, if you put restriction reaction right on gel, it would get distorted and need to be desalted before running on gel (add 2.5x volume of 100% ethanol, overnigh on -20 C (or hour on -80 C) spin 10 min/12 000 g/ 4 C and disolve in appropriate ammount of MiliQ water). I did several restrictions with a very small band with this, worked nicely.
Generally runing on higher voltage/shorter time will make bands less diffuse, but buffers don't like higher voltages and warm too much and conduct worse. SB is a better conductor.