A pro would NEVER EVER try to speed up the curing process by adding more catalyst or more heat.
All the professional boat builders and fibreglass specialists I've known or worked with over the last 50 yrs adjusted catalyst according to working conditions, specifically temperature and thickness applied. It's not about 'speeding up' but maintaining a normal cure time. For example, a mixture ratio suitable for 25* summer heat would still be uncured a week later in winter. Naturally, this issue does not occur in temperature and humidity controlled yards, but usually only the Lloyds-approved ones are - at increased expense. Here we're talking a DIY tank template where none of the criteria that apply to, say, boat-building, apply.
Woven roving cloth will easily conform to a tank contour without darts or folds - unless you are using really overly heavy stuff.
Like to see that. Bit like trying to force plywood into double curvature.
But you see, the whole point is you're trying to compensate for low (incorrect) lay-up temperatures by changing the mix. If it's important, the job needs to be done in the recommended temperatures. It's a misunderstanding of the chemistry involved. Simple!
Pool builders, fairing makers, boat builders are not good guides - near enough is good enough for them.
I've built performance-critical aircraft fuselages, and jobs like this require absolute accuracy, there are no short-cuts.
Obviously you're using too heavy a cloth if you can't get it to cover a compound surface. Use a lighter weight cloth but with more layers is the tip. Cloth is designed so that the strands can slide over one-another, thereby allowing it to cover compound curves.
