Not really if I'm honest, nor for winter crops for that matter. Yes, 25cms. I expect there are some varieties that would be better than others, but I haven't been doing it long enough to find out. Only do bits with it as a cheap and cheerful experiment drill. Works well for rape though
Claydon are 33 cm but you do get more banding which reduces the inter row gap down to around 25cm. I'm happy with winter crops as they have more time to tiller out & NIAB TAB work showed no yield drop up to 25 cm. My concern is a dry and late spring for spring barley where the crop doesn't fill the gaps in, wasting sunlight that hits the ground weeds & won't be turned into yield of malt/flour etc. In theory it ought to change canopy management thinking for pgrs and fungicides.
If you'd gone with Dutch openers you'd have a big selection of seed widths. Spaldings now sell them.