Walrus woes:
For several years I've done washes and filters with Meda Com.Art acrylic paints. They're not really made for styrene (although their opaque white is a cracker jack paint for a fading snow effect) but the disadvantage works for you. They resemble clay washes more than anything else (Flory's probably the best and maybe only). But not really. Unlike any acrylic paint I know, you can at least partially reactivate your work with perhaps warm water or the lightest airbrush cleaner you know the day after application. So you can remove or redistribute what you don't quite like.
Where I really like this stuff is filters. Half the colors in the Com.Art range are "transparent" , half opaque. To be honest, I'm really not sure what the agent is in Com.Art. But when sprayed (or hand brushed) it has a kind of grainy texture - not visible but there. Add a tad of say "transparent smoke" or black and don't try to remove every bit of paint and the result is a kind of genuinely grime feeling and look. To me, that's an advantage. I know this is repetition for most. But if you apply a pinwash (waken up certain points) it requires a satin or gloss finish so the paint beads up and doesn't fall into the general surface. (I must admit that I've grown fond of spray cans for creating a quick satin or gloss finish.) A filter must go on satin or flat finish - the flatter the finish the less easy to make too many changes because the paint will get deeply into the finish. The same factor makes it possible for a highly thinned filter to make subtle changes in surface color/variation. (This is all relative: if something goes wrong it's possible and really not hard to strip most of a model of mega-screw ups and start over.) In a filter, often done nowdays with oils, Com;Art is splendid, especially if you use transparent colors that are highly thinned. (Stuff works so well that hand brushing works great - make a filter you think that won't show much if at all, dab it on with your biggest brush, and check things in about 3 minutes. Add more, throw in some extra colors - I think filters beg for paint mixing - or even take some off. ) When modelers like Mig Jimenez/Adam Wilder or others in the "Spanish School" they were successful enough to completely alter what was expected for a "weathered" model. And they and others have made a mini-industry out of making products that most of us should be able to make ourselves. Personally I don't complain. I still greatly admire the idea put forth by past armor-guru Tony Greenland who said he chose to model German tanks and not the mud they fought in. Ship modelers can literally try to "model a model" - no warship ever appears spanking new out of the water but every single one of them had design models of the ship type that cost $thousands a piece to make and sit in the homes of some of the world's most important naval-industrial types and museums. As far as planes go, every one of them started new. Anyway, do what you want and history supports you. Model anything like the above and you are faced with creating an extremely solid build with a deep and consistent paint job - no easy matter.
Mig and company (like the formidable Mike Rinaldi) counter with a twin argument - 1) military machinery is never clean people using it don't care especially in wartime 2) modeling is a hobby, a craft, and if you want to push for an extreme example of a heavily "distressed" ship, tank, plane, rusted pickup etc, it's your choice. You find examples of real world machinery that looks that way - or close - and it's up to you to try to create your own type of impact. However, one criticism of the Mig, Wilder and others is spot on: you can use heavy weathering to hide mistakes. You can also use it to mitigate poor build. And I would never overestimate the ability of anyone who looks at a friend's model to think "bloody rotten seam line there." And you're dealing with seaplanes - they're like biplanes - there's just an inherent "neat" factor in all of them. Hasegawa still collects full price for their Kawanishi AK71 kit which is 45 years old and by all accounts a bad model. Methinks that if you get the Walrus done, even if it's a big rough around the edges, (considering It's the kit equivalent of a 1962 Ford Falcon) I bet a lot of thumbs up will follow.
Eric