Not sure if that'll work, but have you looked at the Ameriglo Hack
sights? They use the ProGlo front sight with a serrated all black rear sight with what appears to be a similar slanted profile to the Heinies.
If you'd prefer the Heinie rear you could contact them and Ameriglo and see if their rear sights are the same height, if so then you should be good to go.
Ameriglo offers many different front sight heights. Find out what height front sight the Heinies require, and order the correct front sight from Ameriglo. I mix brands all the time.
Thanks for the replies. I really like that Hack front sight. Looks the same as their "Pro-Glo" model, if I'm correct...? I emailed Heinie and I'm waiting for their reply on what height front sight I need to work with their Slant Pro rear. I'd like to combine the Pro Glo front with the Slant Pro rear...I guess I'll see what they have to say and go from there. Thanks.