gpt question

[mlh%goathill.org@localhost (MLH)]

I have a gpt partitioning question that I can't find an answer to.

My old bios doesn't handle UEFI booting correctly but I managed
somehow to get it to boot off of a 4T disk without UEFI through a
long manual process filled with a long forgotten number of trial
and errors. Unfortunately, just about the time I got it working
the *new* drive started failing so I got another new one. In this
case wd1 is the old new drive and wd0 is the new.

This actually boots. Yay!
$ gpt show -l wd1
       start        size  index  contents
           0           1         PMBR
           1           1         Pri GPT header
           2          32         Pri GPT table
          34      100000      1  GPT part - boot1
      100034    10000000      2  GPT part - swap1
    10100034  7803937101      3  GPT part - raidw1
  7814037135          32         Sec GPT table
  7814037167           1         Sec GPT header
 
This doesn't and I do understand why.
$ gpt show -l wd0
       start        size  index  contents
           0           1         PMBR
           1           1         Pri GPT header
           2          32         Pri GPT table
          34          30         Unused
          64     2097152      1  GPT part - boot_h1
     2097216     8388608      2  GPT part - swap_h1
    10485824  7803550936      3  GPT part - root_h1
  7814036760         375         Unused
  7814037135          32         Sec GPT table
  7814037167           1         Sec GPT header

I partitioned it using:
gpt create wd1
gpt add -t ffs  -l boot_h1 -b 64 -s 1g wd1
gpt add -t swap -l swap_h1 -s 4g wd1
gpt add -t ffs -l root_h1 -a 4k -s 7803550932 wd1

I don't understand where the Unused partition came from. How should
I have created the partitions such that it wouldn't have been
created?

I have already moved everything over to root_h1 and I really would
rather not risk losing everything since the old drive is close to
failure. Unfortunately I didn't catch the partitioning error before
I started moving things over.

Is there a way to merge the Unused partition with boot_h1 without
disturbing root_h1? I can easily reinstall boot_h1.

Thanks