I know they're not supposed to be trimmed but his coat is very long- he treads on it at the front when standing up. I'm also concerned about how weighed down he'll get in snow and how long to clean and dry him every time.
I also want to do a hygiene trim, around his butt and underneath.  I've done his butt, badly but not underneath.

I've got straight scissors and half and half (sorry don't know correct terms) I think the teeth may be too close together or maybe I should have full thinning sheers.

Can anyone suggest what's best, number of teeth, teeth on both sides, length of scissors and anything else?   TIA

Hopefully marrianne goldmali will see this.ahea your lady for all things papillon

For snow, I'd simply pop a coat on that keeps the chest dry. Although I've only ever once had a Papillon get weighted down by snow, and that was in 2010 when we had such a lot, and it was my smallest bitch who only weighted 2 kilos. Otherwise, if you're not showing, no problem if you want to trim some long fur off -I know what you mean as my oldest bitch, since being spayed, has such a long coat it pretty much reaches the floor. I don't personally do it though, even with the ones that are now just pure pets. Sticking to fortnightly baths (weekly is required by the type of male who keeps peeing on his coat -two of my three entire ones are) I don't really have a problem. If you choose to use thinning scissors, the ones with one tooth side and one plain will remove more than two sides of teeth.

Thanks so much for your reply Goldmali.

I've tried him with an Equafleece, but I think it was a bit too big as he got it off in less than 10 seconds when I turned my back - little monkey..   I do think I may try another coat,  as you suggest (I already had this onefrom Pip being a pup) as I don't want to spoil his coat - I'm just confused about what is the best way to go.  It'll be interesting to see if removing his retained testicle only will affect his coat, when I eventually find a vet that will just remove that one.

He's actually getting the hang of cocking his leg up properly now (yeah!) the advantage of having a big brother, even though it's taken a while.  

I've totally confused myself about trimming, I've watched so many videos but there's not many with single coated breeds, other than those having paw trims or being shaved. Paw trims are good but not the rest.
Thanks again

Might be worth looking at Yorkie Pet trim videos on how to shorten a long coat without shearing.

Thanks Barbara, that's a good idea.