parlay boost maths

Got a parlay boost offer on a set of games and I started trying to figure out if the extra juice is actually worth it or just another way to lure us into riskier tickets. I know the book gives better odds, but they’re still booking it on their terms so obviously it’s not a charity. If you’re consistent with smaller bets you can usually grind out some value, but these boosted parlays make me feel like I’m being nudged into playing it like the slots - flashy, but eats your bankroll fast if you get carried away.

I like my numbers straight and simple, but math for boosted parlays gets confusing. If the boost gives you, say, 20% more, is there an actual sweet spot for how many legs you play before the variance just destroys any edge? I mean, is there a basic formula or shortcut you guys use to decide if the boost is worth it, or do you just take a shot when you see a matchup you like?