For Lucy in place of OP10 Cavendish

So I'm going to try to copy this deck but there's a few caveats - rather than spend all that money on Gol D Roger, I was going to just run OP07 Dragon and swap out the Rebecca's for Belo Betty, the main idea being that I already have those five and I have no idea how much it'll cost me for Rebecca and Roger combined once OP15 releases.

That being said the OP10 Cavendish is also a high cost that I don't feel like spending $45 for so I'm somewhat stuck - my options are more copies of OP15 Cavendish along with Sai and Chinjao, and if I have a spare slot remaining then ST10 Luffy for now, who'll be replaced by Dragon in the near future. I feel like it's sort of a 3 way tie between the other OP15 cards so I'm not sure if I should include some ratio'd amount or what:

Sai is a 5c 6k blocker while Chinjao is a 4c 5k, both have 1k counter and both on play trash an event to draw 2, while Chinjao makes my opponent bottom deck one of their cards if he gets KO'd on their turn. OP15 Cavendish is a 4c 4k with 2k counter and gets +2k if there's at least 4 events in my trash but otherwise adds no cards to my hand. I get that the optimal thing would be to have the OP10 Cav but I'm not paying that kind of cash, so I feel like maybe something like 3 Sai and 2 Chinjao would be a good balance, gives me some draw and some utility plus some counter if necessary.