Try
www.dillglove.co.uk - this is a shop in birmingham that will let you try out multiple ones (real SMPs I mean), and post them to you. You then post them back after a week or two, which is long enough to try different angles/setbacks and even do an audax on one if you like.
I would recommend doing at least say 30-50 miles on it before deciding - as I tried the avant which is the widest/softest one, and it is
really comfy for about 10-20 miles, but starts to get a bit chafe-y after that.
Personally I wouldn't get a cheap chinese copy as I think you get what you pay for, and you almost certainly can't try before you buy - so you may end up paying for several and still not have one you like.
If you go down the dillglove route, yes although they are expensive, you will only have to pay once, if you find one you like - and not at all if you don't.
Then again that's just me, if you get lucky and find comfort in one that costs you under £50, good on you...
I tried about 5 different ones before finding the one I like which is so good I've never looked back, and have got one on both bikes. I used to love brooks but once I realised that they get 'past it', and the break in point is actually
not the start of bliss for life but merely the pinnacle after which it goes downhill from there descending towards sagginess, that was it, I had to switch to something that stays the same shape. The other thing I noticed is the one I got was so comfy I got one for my tourer as well to replace a brooks B17 that I didn't think was even that bad, but going back to it after several months it felt awful - like real pressure in the central area. Which makes me think the SMP is really supportive in the right place once you get used to it.
There are almost as many different types of SMP as there are brookses - if not more! Also, it's not particularly obvious/intuitive from looking at them which is the right one for you - e.g. the one that looks the widest isn't necessarily the one with the widest
effective width, etc. - this page explains more
https://www.stevehoggbikefitting.com/bikefit/2011/09/all-about-smps/
