sk734,
If you are going to be pulling the trailer with the 2014 Silverado HD listed in your profile,
the online
2014 Silverado 2500HD Owners Manual states that a WDH is not required if the tongue weight is less than 1500# (standard box) or 2000# (long box).
The manual also states that, if you do choose to use a WDH (which, IMO, is a wise choice), the WDH should be adjusted to eliminate about 50% of the front end rise which results from attaching the TT with no WD applied.
As far as I can tell, the Equal-I-zer WD bars are rated on the assumption that the bars will be used to transfer enough load to make the front and rear of the TV "squat" about equally.
The amount of load transfer required to achieve equal squat would be significantly greater (approximately 3-4 times greater) than the load transfer required to achieve the specified 50% elimination of front-end rise.
Even if you would opt for 100% elimination of front-end rise, the required WD bar loading would be only about 55% of the "equal squat" loading.
This means that, whatever realistic tongue weight you expect to have with your 8700# GVWR trailer, IMO you will not come anywhere close to exceeding the load capacity of the EQ 1000# bars.
Also, you should be aware that EQ's "1200#" bars and "1400#" bars are reported to be the same bar.
Based on their dimensions, they would be about 40% stiffer than the 1000# bars.
IMO, the 1000# bars are more than adequate for your tongue weight and should give a softer ride for the TV and TT.
Ron