since I have a pen with a Rotring Renaissance with an OBB-Nib and love it, I was hoping for getting some recommendations for right obliques for a change. They seem unusual and rare, but seem to be a good choice for block letter-style handwriting with wide downstrokes (well, in my theory at least)
I find them very nice exactly for what you say: easy wide downstrokes on "natural" cursive.
I’m also planning to get another left oblique in Medium or Broad, since Double Broad is a bit too hefty sometimes.
And is it worth it to invest in a gold-nib for oblique grinds?
I’m thinking about getting one of the older Pelikans (like the 140 for example) with an OM-nib, since I can get them for under 100€ or an used Montblanc 146 with an OB-nib since I read some good things about them. I also think I found an auction with a cheap UK-made Duofold International where the owner has troubles to determine the nib, but it looks like an Oblique Broad on the pictures.
Since Obliques are offering line variations already, I’m mainly looking for a smooth writing experience without skips and not too costly options.
Right obliques come with a nice side-effect: they also naturally align the tines perpendicular to the downstroke so a semiflex also comes to naturally spread them on the downstroke, multiplying its effect with no thinking about it. IMHO, if you feel comfortable with a right oblique, it pays greatly having a semiflex one.
I'd start, i.e.: with a Pelikan 140 (since you say you are comfortable both with price and size) with a nice semiflex B nib and I'd send it to regrind as RM. Remember that when regrinding a straight point into oblique, it gets wider, so take it into account.
To avoid innecessary risks, instead of regrinding and old gold nib, I'd start with the modern steel ones, since they are cheap and are still produced (don't exactly know about the 140 size, but if not, the M200 will be for sure). That way you can try first which angle you find yourself more comfortable with. You only need to remember -or let the nibmaister know, a modern nib will most probably be a "blob" and you'd want it with a more "stubby" shape. That's also why I consider starting with a vintage B instead of M: B's tend to be originally grinded more stubish, while M's are more like niddle-points.