Re-reading the original post, maybe Spaceman Spliff should consider a mechanical pencil? Won't run dry when stop/starting; inexpensive to buy and feed. The 0.5 and maybe even 0.7 mm leads might break too easily under pressure, so I'd go for a 0.9 mm lead, which will, even without breakages, last a great deal longer. It's also smoother. pencil lead won't survive like FP ink on paper that's subject to much friction, but in notebooks that aren't subject to rubbing, as opposed to notes thrust into busy pockets, that might not be a problem.
Inexpensive, with a big comfy grip: Pentel Twist-Erase £5.39 available for 0.5, 0.7 and 0.9 mm leads (review here).
Pocket safe, heavier, with a grip that is far more comfortable than you might imagine: Pentel Graphgear 1000 £12.49 available for 0.9 mm lead and a whole load of smaller sizes (review here).
Available in 0.9mm only, the Platinum Press Man MPS-200 £2.99 has a cushioned lead mechanism to make writing smoother and further protect lead from breaking, and it's pocket safe. Slimmer in the grip, which is achieved by means of circular grooves in the plastic body. I can't find a review, but I'm sore tempted myself.
No affiliation with this seller, other than as an occasional customer.
If an FP really is the only answer, the only FP in my possession which has never, ever, ever dried out or failed to make the required mark on paper, never missed the first downstroke after a pause, is a Pelikan M250. I don't know whether this "runs in the family", so to speak, or it's been sheer dumb luck. But I wouldn't allow anybody with a heavy hand to use it, as replacement nibs will cost £20 or so.
I did think maybe one of the bigger Esterbrooks, with a new sac and a manifold nib, built for writing carbon copies, though perfectly comfortable for ordinary use. The nib units are easily swapped out if they come to any harm.