Recto is now my favorite amp in the box, its come a long way in FW18, doesn't require as much tweaking now. Mainly I've been using Recto2 Red Mdrn. Many prefer Recto1 but I seem to be one of the few who prefer the sound of the three channel rectos for whatever reason. These are my go-to parameters to tighten it up.
1. Low Master Volume. I have it set at about 2. If its too high, the bottom end distorts too much, and it gets flubby.
2. Use the 'Cut' parameter
3. If you're not using a boost, turn up the low cut frequency on the dynamic EQ page (or advanced page? I forget). This cleans up and tightens the bottom end. Its also useful for when you are using a boost. If it thins the tone too much, try adding the bass back with the GEQ Page.
4. T808 Mod - low to no drive (between 0 and 2), high level (6 to 10) and tone to taste (I usually have it all the way up). Higher level on the pedal and lower gain on the amp = tighter sound, and vice versa.
5. PEQ in front, cutting lows and boosting highs helps if you don't want to use an overdrive. I've been using a PEQ in front lately. I've set a low peaking filter at 100hz and high peaking filter at 10,000hz, with very wide Q's (almost as wide as it goes) cutting a ton of bottom, boosting a ton of highs, and then a big level boost. Its what I assume the TC Electronic Integrated preamp sounds like, as those are its center frequencies for the Bass and Treble controls. Dunno if the Q is right though.
6. Turn up Poweramp Hardness, as stated earlier. It will have less/no effect on the sound if your master is really low though.
7. Turn down poweramp Sag - though it now defaults to a fairly low setting. In previous firmwares it defaulted to a fairly high setting (I assume to simulate tube rectification?) and it benefited from being turned down. Now, it seems fine as-is, imo. Beware - turning this parameter to 0 will turn off poweramp modeling.
As far as the basic EQ, the treble tends to scoop the mids as you turn it higher, so compensate by turning up the mids. I also keep the presence really low, like 0.50 or so, just because it adds a lot of gross top end, and strangely seems to make it less chunky sounding when its higher (imo).