would you mind telling me what augments you would suggest across three or four capes?
Sure.
While you may have a lot of materials, just in general, I'd point out that there's no inherent need to augment every slot on a cape. Many are also already quite good with the relatively cheap Thread/Dust/Sap augments. Dye and Resin were added later, and their higher cost reflects their "give players more to do" purpose.
Anyway...
Your first WHM cape to make is your general casting one. 30 MND (20 Thread + 10 Dye), MACC/MDMG (Dust), and either Fast Cast or Haste from Sap would be ideal, though that slot is a bit flexible.
With Fast Cast, this makes for a pretty solid all-around cape for those looking to conserve materials or inventory. On the other hand, Haste puts a bigger potential dent in recast timers, and is probably the way to go if making more than one cape.
Alternatively, as mentioned, you could use the Sap augment for -Enmity.
The second cape to consider then, is your Fast Cast cape, which can also be set up as an Idle cape since Sap is the one augment that really doesn't offer much towards that. In that case, EVA/MEVA from Dust, MEVA from Dye, with Thread/Resin maybe being more a matter of preference. I would probably do HP and MEVA for them respectively, but MP/MND/INT would have merits, as would PDT.
-alternatively-
You could opt to flesh out your Fast Cast cape with INT and MACC, for subjob spells. I do this the other way around for SCH/RDM/BLM - MAB on the INT cape, Fast Cast on MND.
Beyond those, I'd really look at how you use the job. If you're only ever using it for backline support, then the materials/inventory for additional capes may be better used for other jobs.
Before melee, I would again consider more niche spell uses. An INT cape maybe. A MAB one for Banish/Holy (someone did post about hitting Omen objectives with that).
Melee capes, for any job, can expand quickly if you try to optimize for every possible situation or WS.
The standard setup for a TP cape, for most any job, tends to be DEX from Thread, ACC/ATT from Dust, and either DEX or ACC from Dye. Double Attack, Store TP, or Dual Wield can be good uses of the Sap slot, depending on job, buffs, and what other gear you have.
Your general setup there is likely going to be DA. DW for /DNC (/NIN can get needed Dual Wield to cap with full buffs from, say, Suppanomimi and Shetal Stone). STP is probably only worth considering for Yagrush AM3. So, I would make a DA TP back first.
It's common to put a PDT augment in the Resin slot for a TP cape as well.
WS, on the other hand, tend to favor whatever primary mods the WS has, and then DA, Crit, or WSDMG. Offhand, I think you'd want MND/WSD, STR/WSD, and STR/Crit to cover most club WS?
To a point, I'd step back and consider how seriously you're approaching WHM melee. If you're only looking at low tier stuff, maybe that you don't need the extra 15-22 ACC from DEX for, I'd look at doing a STR/DA melee cape to start. As nearly every club WS is STR and/or MND mod, that or your MND cape would be decent.
When you can build more capes, and if you're still seeing the need, use a Needle to change the STR to DEX, and build the more specific WS capes.