Prop to Pad height--4 blade vs. 3 blade

[STEVE81]

So I recently bought a Fury 4 to try on my boat. I have been running a tempest plus (3 blade, if you're unfamiliar) at 2.75" below pad. On a tournament load with just me, I see about 73-74 mph on average but it is a dog out of the hole if I fill a livewell or have another person in the boat. Not to mention losing anywhere from 4-8 mph. Because of that, I decided to give a 4 blade a try. My question is, what is a good starting point on a prop to pad measurement for the 4 blade? My current stats are below:

Currently have a 26P Tempest plus at 2.75 below pad.
6" manual jackplate with 2" spacers
2007 Tr21X w/ 250 Pro XS (silver gear case)

Going to a 25P Fury 4 that has a tiny bit of cup added to it.

If there is more info needed to be helpful, let me know.

[Savage]

Start at the same height, but you may have to go lower......every boat is different. A Bravo1 XS would run at the exact same height as the Tempest.

[STEVE81]

Start at the same height, but you may have to go lower......every boat is different. A Bravo1 XS would run at the exact same height as the Tempest.

Well that's good to hear! I hate having to mess with that jackplate any more than I have to.