There are two ways to approach this.
First - don't produce any liberty bells so your rebel sentiment stays at zero and the REF doesn't increase. However build printing presses and newspapers in your colonies and hire or train elder statesmen (but don't put them in the town hall). Then when you have built up your own forces make a late run at rebel sentiment by filling all your town halls with those elders. By the time the King realises what you are doing you have hit the 50% mark and can declare independence facing a tiny REF. I hate this approach
Second - play the game the way it was intended with a balance between all elements, including production of liberty bells. This allows you to grab your share of founding fathers as well as expanding your colony boundaries and also increasing the production within those colonies. Yes the REF will steadily increase, but so what. It only gives you more troops to kill at the end. The REF does not arrive en masse, they just trickle in and you can wipe them out with your dragoons as soon as they land. However don't let them attack your colonies, they have a very strong attack but poor defence. You can defeat the REF at odds of up to 9 to 1 against if necessary.