I don't know if you've used the Mark V HPS but it's actually quite quick. A very popular rubber in Japan. Suitable for most club players. A good rubber.
If you're talking the Yasaka range, Rigan is a better option than Rakza 7 soft imo. More tolerance and easy to play with, with good spin 👌
Nope, I'll have to take your word for it, but I would still advise against it and here's why:
As a (fairly) new player, there is still a lot of room to grow. Mark V HPS is like a 50s race car on steroids: it's essentially a racing car, but simply not made for this game. You can adjust is with modern suspension and better tyres to make it much faster, but the problem is it's built on an old chassis.
The chassis (the Mark V topsheet) works nothing like modern ones. It has good grip, one of the best (if not
the best) of its era, which makes that it can still come up not too far short in today's game - but it does come up short.
Compare it to a semi-modern tensor (Rakza 7 is 2010 and the first wave of Tenergy competitors) and we're talking conceptually different rubbers, built with a philosophy that is still applicable to today's game. You can learn basics with this type of rubber that are transferable to top range rubbers like Dignics and Zyre because in essence, those employ the same tensor effect.
You can't learn the same methods of applying spin with a Mark V topsheet, unless you also want to go and apply speed glue and get the effect that these newer rubbers are trying to emulate.
There's a player at my club, quite decent (better than me) but also quite a few years older than me, who switched from Mark V to R7 soft on his BH a few months ago and while he's still getting used to it, his balls are simply better quality. More spin, faster, he has a much easier time opening up and attacking. That's what a topsheet from this century does vs one that was made half a century ago. And the sooner you make this switch, the more you're going to be able to learn to play it like it's supposed to be played.
I understand club players, especially those who have been playing Mark V for a couple of decades, will simply keep with the fastest Mark V-like option they can get their hands on. And that's fair game! But they have hit a ceiling by sticking with that and will never be able to produce the quality of balls required to move up.
Rigan is an interesting suggestion. I had to read up on it because somehow it looks like an old rubber and I've always ignored it because of that, but it seems to be even more of a friendly entry into tensors (like Vega Intro or something). Good idea if the step to R7(s) feels too much.