As someone who's spent more than the last year trying to learn handstands as an adult, they're seriously hard. I don't know how long you've been practising, but I totally underestimated how long it would take me to balance one. I was starting from being pretty out of shape and I'd never done anything like this before, and I'm also tall (6'4"/194cm) which makes it harder, but I see people talking about timeframes of 6 months to a year minimum of training them seriously (say 20-30 mins 4x a week or more) to have a chance at kicking up into a free balancing handstand for, say, 15-20 seconds. It has taken me way longer than that, but I'm now up to ~30 sec holds but still with pretty terrible consistency (i.e. I get a couple of good holds and a few more shorter ones a day out of ~20 attempts).
For where it sounds like you're at, I totally recommend Yuri Marmerstein's Vimeo series here: https://vimeo.com/ondemand/handstandbalance/249766384. Not free but cheap and very good. The basic requirements are being comfortable bailing, and being able to hold a half-decent chest to wall handstand.
re: body tension, it depends what you're planning to achieve. For just handbalancing you actually don't need a lot of tension, just enough that you're not flopping around all over the place. Most of the information online that talks about buns & core of steel comes from gymnastics, where the tension is used to generate force when tumbling. Most people from a handbalancing background no longer recommend tons of ab work (i.e. dish/hollow body) since it's not really required. You will need tons of trapezius and forearm strength though, working those was really a game changer for me.
For where it sounds like you're at, I totally recommend Yuri Marmerstein's Vimeo series here: https://vimeo.com/ondemand/handstandbalance/249766384. Not free but cheap and very good. The basic requirements are being comfortable bailing, and being able to hold a half-decent chest to wall handstand.
re: body tension, it depends what you're planning to achieve. For just handbalancing you actually don't need a lot of tension, just enough that you're not flopping around all over the place. Most of the information online that talks about buns & core of steel comes from gymnastics, where the tension is used to generate force when tumbling. Most people from a handbalancing background no longer recommend tons of ab work (i.e. dish/hollow body) since it's not really required. You will need tons of trapezius and forearm strength though, working those was really a game changer for me.