Ever person I talk with says not to use one. I personal have had a lot of problems because of one. Do a search for earl brown timing cover mod and do it.
Use a thrust plate. The best thing about using one is you can measure the thrust clearance by bolting the thrust plate by its self with a gasket and checking the thrust clearance of the gears with a feeler guage through the hole where the gears are exposed. TA PERF sells a shim kit if you need more clearance. If you need less you can reduce clearance by sanding your gears on plate glass.
I honestly have never had any problem with a HV unit but that doesn't discount that others have. On most of my builds the mains are enlarged so a HV unit is required to keep the pressures up. I have been using HV units from fullthrottle on the last 3-4 setups I've put together and they have all been great so far. I even do the Earl Brown mods to the HV covers with no issues.
I run a cleaned up stock cover with standard length gears and have never ran a HV pump. I have not had a problem on any of my engines. Oil pressure was never a problem. Still hits the pressure relief when the oil is really hot.