Hi James, please don't give up on these kits just yet. It's an old Trumpeter kit that I'm working on for this campaign. Yes, they are dimensionally challenged, and yes, they do need a bit of upgrading to get a decent result but if you want a Chinese type 59/69/79 then you will be spending money on conversion kits even if you've started with the more expensive Tamiya T55. I chose to start with a Trumpeter as my basis because, well, I suppose I'm just a bit perverse that way.
Talking of which, you also mentioned the Meng T90. I'm half way though building this kit (in parallel with Zvezda's example) and I can't say it's a thing that I love. The plastic has a strange rubbery consistency to it and I've had a couple of problems with mal-formed parts owing I guess to flow issues in the moulds, indeed one part was missing altogether! Having said that I hope it lives up to your expectations, and anyway I did say that I am a bit perverse.
Anyway back to the GB. Here's my progress with my Trumpy based Type 69-II.
First off I had to ditch the spider-web wheels and nicked some from a Dragon NVA T34/85 that I had in my stash.
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But then I realised that these weren't quite right so after a lot of agonising I decided to steal a set from my much-prized Tamiya T55.
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Sprockets from a Trumpeter T62...
and idlers from the original kit.
Also had to modify rear hull plate (fan bulge yet to be added).
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Trimmed then thinned down the track guards...
so here's how it looks so far...
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Oh, and don't worry about the T55, I have plans to build it as a real bitza from the Balkans conflict where anything really did get used to keep their hardware running.