Basically what I do is have these little banners after my updates on tapas, sometimes mentioning my patreon and sometimes mentioning my premium comic. On Webtoon i used to do that too, but with the new policy change I don't have to have the premium comic banners over there. Thanks to the notices about the policy, people already move to tapas and then they are much more likely to latch onto my premium comic from there since they are now on the correct platform.
Going back a month or two I would get 20-50 subscribers a day on the comic, now with my free comics posting actively on both webtoon and tapas I get 100-140 a day. Active readership is a bit different, but my comic has also spiked in both active free readership and active paid readership since said comic became Wait-or-Pay so that helps too.
It's hard to track what the exact conversion rate is here since webtoons stats are not as detailed as the tapas dashboard stats. But for comparison, Moonshine gets about 180-250 subs a day on Tapas and I think the majority of audiences are coming in through that one, so that's about a 50% movearound rate of subs? take or give
Tapas readers definitely do have a higher will to purchase things, but I think that has to do with age and the maturity and most noteably ABILITY to buy things online that comes with that. Tapas audience is on average slightly older than webtoons audience.