Based on several years of infield experience, it's harder to isolate HB9s and HB10s due to their wider social circle (cockblocking friends). On the other hand, it's easier to isolate HB6s up to HB8s. There are always exceptions of course but that's the general rule.
HB9s and HB10s are rare. But for the HB9s that I did f-close, the only way that you can isolate them is to make them super horny about you. How do you make these hot girls super horny? There are many ways like sexual innuendos, dominant body language, testosterone boost, dopamine (girl's dopamine) boost, the very reliable eye fuck, and so on.
More experienced PUAs might have other field tested techniques but that's what I can only provide you for now. I may have several years of infield experience but it's only the past few months that I'm actually sarging X 10 more girls than I used to sarge at any given instance.

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Approach. Open. Escalate. Isolate
Here are my two essential rules on texting that will save you tons of time and money:
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