Scale Aircraft Options for Khalkin Gol

I've worked out that I need about eight to ten of the basic fighter types for the Khalkin Gol / Nonomhan Bag the Hun scenario project, with the obvious choice being either 1/285th - 1/300th or 1/600th. Luckily, the main fighters are readily available in both scales, with Raiden Miniatures, Heroics & Ros and Scotia Collectair filing the 1/285th - 1/300th scale gap, and Tumbling Dice or Oddzial Osmy providing the 1/600th scale models (I've included pictures of the I-16 models for comparison).

Here are the relevant codes for the Raiden Miniatures option:

RAI-RUS001 - Polikarpov I-16 (£2.50)

RAI-RUS009 - Polikarpov I-15bis (£2.95)

RAI - RUS011 - Polikarpov I-153 (£2.95)

RAI - JAP025 - Nakajima Ki-27 (£2.50)

For a considerably cheaper option, Scotia Collectair has the following:

CAR-S12 Polikarpov I-16 (£1.00)

CAR-S20 Polikarpov I-153 (£1.00) - listed as an I-15 but it's a Chaika!

CAJ-S11 Nakajima Ki-27 (£1.00)

CAJ-S19 Kawasaki Ki-31 Mary (£1.50)

CAJ-S22 Mitsubishi Ki-51 Sonia (£1.00)

A good option for a cannon armed I-16P?

If you can find some, Leading Edge also used to have a Ki-27 in their range but it's now OOP.

The Heroics and Ros range also includes a good number of the planes you need, including an R-5:

JA108 - Nakajima Ki-27 Nate (£1.00)

JA115 - Mitsubishi Ki-15 Babs (£1.00)

JA116 - Mitsubishi Ki-51 Sonia (£1.00)

JA208 - Kawasaki Ki-32 Mary (£1.25)

JA305 - Kawasaki Ki-10 Perry (£1.50)

SA101 - Polikarpov I-16 (£1.00)

SA304 - Polikarpov R-5 (£1.00)

In 1/600th scale, Tumbling Dice has the following at a standard pack price of £2.00:

ISA336 - Polikarpov I-152 (I-15bis) x 4 

ISA367 - Polikarpov I-16 x 6

ISA373 - Polikarpov I-153 x 4

ISA403 Kawasaki Type92 Ki10 x 4

ISA411 Nakajima Ki-27 x 4

If you prefer Oddzial Osmy, here are the relevant codes, at £4.00 per pack:

WSU616 Polikarpov I-16 x 8

WSU627 Polikarpov I-153 x 8

WJA607 Nakajima Ki-27 Otsu x 8

Please remember that I've omitted any of the medium bombers, as they don't feature in the scenarios I'm working on, but there are some available in both 1/300th and 1/600th scale. 

I think I'll opt for 1/600th scale using the Tumbling Dice range, as it's more cost effective and has everything I need apart from a Polikarpov R-5, which I will have to convert from something similar. If I had deep pockets and plenty of time, however, the Raiden Miniatures models are very nice, with the Collectair option as a back up. The Collectair I-16 and I-153 are actually really decent models and would paint up well, so they would be my first choice in 6mm.