Installed Windows 10 media to USB as "Both" (64 bit and 32 bit). Windows 7 asking for 64 bit. Can I run media as 64 bit?

There is no such option, you either choose 32 or 64 bit.

How to create a ISO or USB drive.

Select Create installation media for another PC then click Next

Choose your language, edition, and architecture then click Next

Please note: The copy of Windows 10 you download must correspond with the edition of Windows you are upgrading from, the architectures must correspond too (32 bit > 32 bit, 64 bit > 64 bit):

• Windows 7 Starter, Home Basic, Home Premium, Windows 8.0 Core, Windows 8.1 Core must use a Windows 10 Home ISO
• Windows 7 Professional, Windows 7 Ultimate, Windows 8.0 Pro, Windows 8.1 Pro must use a Windows 10 Pro ISO
  
• Your currently installed copy of Windows must be activated. If it is not, you will be prompted to enter a product key, if you don't have one, you will have to Rollback and start again.
• You must perform an inplace upgrade, do not clean install. Learn more HERE
• If you are using Windows 7 Enterprise, Windows 8.0 Enterprise, Windows 8.1 Enterprise editions, or volume license Windows 7 Professional you won't be able to use the free upgrade offer.

I suggest you choose the .ISO file option, since you can reuse it for multiple options. Click Next

USB flash drive

If you have a thumb drive with 3 GBs of available space, you can use that to create a bootable copy. Thumb drives are very cheap these days, so pick up a couple and create one as your first backup option. This is especially recommended for persons using Ultrabooks which do not include optical drives (DVD) or Netbooks. There are some desktop systems that do not include one.

ISO file

An ISO file is a digital or virtual replica of a physical disc. In order to use an ISO you must burn it to a optical disc. In the case of Windows 10, a blank DVD. If you are using Windows 7, you can create the .ISO and burn it using the built in Disc Image utility. If you are running Windows XP or Windows Vista, you can using a third party burning tool such as ImgBurn or Roxio/Nero.

Creating a .ISO file

For the purposes of this exercise, we are gonna use the .ISO option.

Select ISO file, then click Save

Select your location and click Save.

Wait while the .ISO image is created.

Prepare Windows 10 ISO file

After you have downloaded the Windows 10 ISO, you need prepare it, this is especially important for Windows 7 users..

After obtaining the .iso file you can use the built in Disc Image burning tool or Microsoft .iso to USB/DVD tool to create a bootable DVD or USB (requires a blank DVD or USB flash stick of at least 4 GB).

After downloading the .ISO file, right click it and click Burn disc image

Insert a blank DVD

Click Burn

Windows 8/8.1 users can mount the .ISO file and start the upgrade automatically. Learn more here

Important:

If you are creating a bootable USB thumb drive, make sure the thumb drive is first formatted as FAT32.

Connect the thumb drive

Open Computer

Right click thumbdrive

Click Format

Make sure FAT32 is selected as the file system.

For UEFI based systems

If your computer is UEFI based, these are normally systems that come pre-loaded with Windows 8 or later, you will need to prepare the ISO file for such a configuration or you will receive an error message during setup. The thumbdrive needs to be formatted as FAT32 and use the GPT partitioning scheme. To do this, you need to use Rufus, a small tool you can download for free.

Rufus - credit: Pete Batard/Akeo

After you have installed Rufus:

• Launch it
• Select ISO Image
• Point to the Windows 10 ISO file
• Check off Create a bootable disk using
• Select GPT partitioning for EUFI firmware as the Partition scheme
• Choose FAT32 NOT NTFS as the File system
• Make sure your USB thumbdrive in the Device list box
• Click Start
• Close when complete

Both IS an option, and I'd selected it. I'll just restart the process though and only select 64-bit.

Try the setup located in the sources folder.