This thread about “light switch” on/off-style switches may be helpful:
Gateron Type R or HMX Retro J may be of some interest, but they don’t feel quite like WS Heavy Tactiles to me, possibly due to the much shorter overall travel. Have you tried the heavier variety of Zeal Clickiez? That gets pretty close while still feeling different enough to not just use the WS Heavy Tactile itself.
Side note, but don’t rule out spring length when considering bottom out force. 22mm two-stage springs provide a lot more resistance than you’d expect and feel at least 5-10g heavier than their posted weights in my opinion.