@Haley R
You have to go into your Membership rewards to see whether you're targeted for the transfer bonus for HH
1) login to American Express
2) on the right there is your MR total and under that, a bar that says Explore Rewards-click on that
3) you're then on the MR page-the 5th tab over says "transfer points" with an arrow, click on that
4) there will be "featured" with a couple of offers (I currently have bonuses to transfer to Jet Blue and Flying Blue) and above it "View All"
5) all of the loyalty programs you have linked your account to will be listed, then under that airlines you've not linked and then hotels (my hilton has the 40% bonus). This is where you see your bonus for transfer, no under Amex Offers.
I know you feel that URs are the way to go and just playing with dates from MCO to LHR, if you're flying economy then you're correct. Having flown multiple, multiple times to the UK in business and first, if you think that's a good way to utilize points, I would respectfully disagree. MCO-LHR is going to be 1 stop on Virgin, Delta, Aer Lingus, American, British Air, TAP. MRs transfer (often with bonuses) to Virgin, Delta, British Air, and Aer Lingus. Taxes and fees to the UK are still high so factor those in when you're planning to pay for your trip.