I would be looking to use larger streamers or small intruders. I would rather use weighted tips instead of weighted flies if possible. So the flies I'm aiming for will be more bulk than weight. I will use my current switch line for fishing indicators or smaller/lighter flies.
The switch line is a skagit, so adding 10 ft tips, either tapered like the rio
, SI, or post tips, or straight pics of T material (I'd go with T8) should work. It will be a little clunky overhead,, but that's skagit.. It should be great sustained anchor spey casting.
And 8 wt wf single hand line should work too. I like the Airflow 40 plus as a scandi or overhead, but most any 8 or 9 weight wf should work.. So anything you can throw with an 8 wt sh, you should be able to throw with the line win your Beulah, and it will deliver more elegantly. You cold also ad sinking poly leaders to that, though I'd probably stick with 5 footers I this case.
I just asked opst today what grain head they would recommend and they said 275 grain head with their 10í0Ē tip. My first thought was that sounded light but Iím gonna give that a try and see how it feels.
Go with the OPST rec's. The OPST heads run "light"- short and fat loads the rod "heavier" than longer and thinner.
And the site is lightly trafficked these days. You probably didn't get an earlier answer because no one who saw it has the rod. I have only cast it once, don't own it, so my thoughts are just general based on length and grain weights.